World War II

World War I had radically altered the political European map, with the defeat of the Central Powers—including Austria-Hungary, Germany, Bulgaria and the Ottoman Empire—and the 1917 Bolshevik seizure of power in Russia, which led to the founding of the Soviet Union. Meanwhile, the victorious Allies of World War I, such as France, Belgium, Italy, Romania, and Greece, gained territory, and new nation-states were created out of the collapse of Austria-Hungary and the Ottoman and Russian Empires.

To prevent a future world war, the League of Nations was created during the 1919 Paris Peace Conference. The organisation's primary goals were to prevent armed conflict through collective security, military and naval disarmament, and settling international disputes through peaceful negotiations and arbitration.

Despite strong pacifist sentiment after World War I, irredentist and revanchist nationalism emerged in several European states in the same period. These sentiments were especially marked in Germany because of the significant territorial, colonial, and financial losses imposed by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all its overseas possessions, while German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces.

The United Kingdom, France and Italy formed the Stresa Front in April 1935 in order to contain Germany, a key step towards military globalisation; however, that June, the United Kingdom made an independent naval agreement with Germany, easing prior restrictions. The Soviet Union, concerned by Germany's goals of capturing vast areas of Eastern Europe, drafted a treaty of mutual assistance with France. Before taking effect, though, the Franco-Soviet pact was required to go through the bureaucracy of the League of Nations, which rendered it essentially toothless. The United States, concerned with events in Europe and Asia, passed the Neutrality Act in August of the same year.

Hitler defied the Versailles and Locarno treaties by remilitarising the Rhineland in March 1936, encountering little opposition due to the policy of appeasement. In October 1936, Germany and Italy formed the Rome–Berlin Axis. A month later, Germany and Japan signed the Anti-Comintern Pact, which Italy joined the following year.

The Kuomintang (KMT) party in China launched a unification campaign against regional warlords and nominally unified China in the mid-1920s, but was soon embroiled in a civil war against its former Chinese Communist Party allies and new regional warlords. In 1931, an increasingly militaristic Empire of Japan, which had long sought influence in China as the first step of what its government saw as the country's right to rule Asia, staged the Mukden Incident as a pretext to invade Manchuria and establish the puppet state of Manchukuo.

China appealed to the League of Nations to stop the Japanese invasion of Manchuria. Japan withdrew from the League of Nations after being condemned for its incursion into Manchuria. The two nations then fought several battles, in Shanghai, Rehe and Hebei, until the Tanggu Truce was signed in 1933. Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression in Manchuria, and Chahar and Suiyuan. After the 1936 Xi'an Incident, the Kuomintang and communist forces agreed on a ceasefire to present a united front to oppose Japan.

The Second Sino-Japanese War (1937–1945) was a military conflict that was primarily waged between the Republic of China and the Empire of Japan. The war made up the Chinese theater of the wider Pacific Theater of the Second World War. The beginning of the war is conventionally dated to the Marco Polo Bridge Incident on 7 July 1937, when a dispute between Japanese and Chinese troops in Peking escalated into a full-scale invasion. This full-scale war between the Chinese and the Empire of Japan is often regarded as the beginning of World War II in Asia.

China fought Japan with aid from the Soviet Union, Britain and the United States. After the Japanese attacks on Malaya and Pearl Harbor in 1941, the war merged with other conflicts which are generally categorized under those conflicts of World War II as a major sector known as the China Burma India Theater. Some scholars consider the European War and the Pacific War to be entirely separate, albeit concurrent, wars. Other scholars consider the start of the full-scale Second Sino-Japanese War in 1937 to have been the beginning of World War II. The Second Sino-Japanese War was the largest Asian war in the 20th century.

The military occupation of Czechoslovakia by Nazi Germany began with the German annexation of the Sudetenland in 1938, continued with the creation of the Protectorate of Bohemia and Moravia, and by the end of 1944 extended to all parts of Czechoslovakia.

The Molotov–Ribbentrop Pact was a non-aggression pact between Nazi Germany and the Soviet Union that enabled those two powers to partition Poland between them. The pact was signed in Moscow on 23 August 1939 by German Foreign Minister Joachim von Ribbentrop and Soviet Foreign Minister Vyacheslav Molotov and was officially known as the Treaty of Non-Aggression between Germany and the Union of Soviet Socialist Republics.

It's clauses provided a written guarantee of peace by each party towards the other and a commitment that declared that neither government would ally itself to or aid an enemy of the other. In addition to the publicly-announced stipulations of non-aggression, the treaty included the Secret Protocol, which defined the borders of Soviet and German spheres of influence across Poland, Lithuania, Latvia, Estonia and Finland. The secret protocol also recognised the interest of Lithuania in the Vilnius region, and Germany declared its complete disinterest in Bessarabia. The rumoured existence of the Secret Protocol was proved only when it was made public during the Nuremberg Trials.

The invasion of Poland was an attack on the Republic of Poland by Nazi Germany and the Soviet Union which marked the beginning of World War II. The German invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union, and one day after the Supreme Soviet of the Soviet Union had approved the pact. The Soviets invaded Poland on 17 September. The campaign ended on 6 October with Germany and the Soviet Union dividing and annexing the whole of Poland under the terms of the German–Soviet Frontier Treaty.

German forces invaded Poland from the north, south, and west the morning after the Gleiwitz incident. Slovak military forces advanced alongside the Germans in northern Slovakia. As the Wehrmacht advanced, Polish forces withdrew from their forward bases of operation close to the Germany–Poland border to more established defense lines to the east. After the mid-September Polish defeat in the Battle of the Bzura, the Germans gained an undisputed advantage. Polish forces then withdrew to the southeast where they prepared for a long defence of the Romanian Bridgehead and awaited expected support and relief from France and the United Kingdom. On 3 September, based on their alliance agreements with Poland, the United Kingdom and France declared war on Germany; in the end their aid to Poland was very limited.

The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.

The Battle of the Atlantic pitted U-boats and other warships of the German Kriegsmarine (Navy) and aircraft of the Luftwaffe (Air Force) against the Royal Navy, Royal Canadian Navy, United States Navy, and Allied merchant shipping. Convoys, coming mainly from North America and predominantly going to the United Kingdom and the Soviet Union, were protected for the most part by the British and Canadian navies and air forces. These forces were aided by ships and aircraft of the United States beginning September 13, 1941. The Germans were joined by submarines of the Italian Regia Marina (Royal Navy) after Germany's Axis ally Italy entered the war on June 10, 1940.

The Phoney War was an eight-month period at the start of World War II, during which there was only one limited military land operation on the Western Front, when French troops invaded Germany's Saar district. Nazi Germany carried out the invasion of Poland on 1 September 1939; the Phoney period began with the declaration of war by the United Kingdom and France against Nazi Germany on 3 September 1939, after which little actual warfare occurred, and ended with the German invasion of France and the Low Countries on 10 May 1940. Although there was no large-scale military action by Britain and France, they did begin some economic warfare, especially with the naval blockade, and shut down German surface raiders. They created elaborate plans for numerous large-scale operations designed to cripple the German war effort. These included opening an Anglo-French front in the Balkans, invading Norway to seize control of Germany's main source of iron ore and a strike against the Soviet Union, to cut off its supply of oil to Germany. By April 1940, the lone execution of the Norway plan was considered inadequate to stop the German offensive.

The Winter War, also known as the First Soviet-Finnish War, was a war between the Soviet Union and Finland. The war began with a Soviet invasion of Finland on 30 November 1939, three months after the outbreak of World War II, and ended three and a half months later with the Moscow Peace Treaty on 13 March 1940. Despite superior military strength, especially in tanks and aircraft, the Soviet Union suffered severe losses and initially made little headway. The League of Nations deemed the attack illegal and expelled the Soviet Union from the organisation.

The Norwegian campaign (8 April – 10 June 1940) describes the attempt of the Allies to defend northern Norway coupled with Norwegian forces' resistance to the country's invasion by Nazi Germany in World War II.

Planned as Operation Wilfred and Plan R 4, while the German attack was feared but had not happened, HMS Renown set out from Scapa Flow for the Vestfjorden with twelve destroyers on 4 April. British and German naval forces met at the first Battle of Narvik on 9 and 10 April, and the first British forces landed at Åndalsnes on the 13th. The main strategic reason for Germany to invade Norway was to seize the port of Narvik and guarantee the iron ore needed for critical production of steel.

The campaign was fought until 10 June 1940 and saw the escape of King Haakon VII and his heir apparent Crown Prince Olav to the United Kingdom.

A British, French and Polish expeditionary force of 38,000 soldiers, many days in, landed in the north. It had moderate success, but made a rapid strategic retreat after the German Blitzkrieg invasion of France began in May. The Norwegian government then sought exile in London. The campaign ended with the occupation of the entirety of Norway by Germany, but exiled Norwegian forces escaped and fought on from overseas.

The German invasion of Denmark, sometimes known as the Six Hour War due to the short length, was the German attack on Denmark on 9 April 1940, during the Second World War. The attack was a prelude to the invasion of Norway. Lasting approximately six hours, the German ground campaign against Denmark was one of the shortest military operations of the Second World War.

The invasion of Belgium or Belgian campaign (10–28 May 1940), often referred to within Belgium as the 18 Days' Campaign, formed part of the greater Battle of France, an offensive campaign by Germany during the Second World War. It took place over 18 days in May 1940 and ended with the German occupation of Belgium following the surrender of the Belgian Army.

On 10 May 1940, Germany invaded Luxembourg, the Netherlands, and Belgium under the operational plan Fall Gelb (Case Yellow). The Allied armies attempted to halt the German Army in Belgium, believing it to be the main German thrust. After the French had fully committed the best of the Allied armies to Belgium between 10 and 12 May, the Germans enacted the second phase of their operation, a break-through, or sickle cut, through the Ardennes, and advanced toward the English Channel. The German Army (Heer) reached the Channel after five days, encircling the Allied armies. The Germans gradually reduced the pocket of Allied forces, forcing them back to the sea. The Belgian Army surrendered on 28 May 1940, ending the battle.

The Battle of Belgium included the first tank battle of the war, the Battle of Hannut. It was the largest tank battle in history at the time but was later surpassed by the battles of the North African Campaign and the Eastern Front. The battle also included the Battle of Fort Eben-Emael, the first strategic airborne operation using paratroopers ever attempted.

The German invasion of the Netherlands was a military campaign part of Case Yellow, the German invasion of the Low Countries (Belgium, Luxembourg, and the Netherlands) and France during World War II. The battle lasted from 10 May 1940 until the surrender of the main Dutch forces on 14 May. Dutch troops in the province of Zealand continued to resist the Wehrmacht until 17 May when Germany completed its occupation of the whole country.

The invasion of the Netherlands saw some of the earliest mass paratroop drops, to occupy tactical points and assist the advance of ground troops. The German Luftwaffe used paratroopers in the capture of several airfields in the vicinity of Rotterdam and The Hague, helping to quickly overrun the country and immobilise Dutch forces.

After the devastating bombing of Rotterdam by the Luftwaffe on 14 May, the Germans threatened to bomb other Dutch cities if the Dutch forces refused to surrender. The General Staff knew it could not stop the bombers and ordered the Dutch Army to cease hostilities. The last occupied parts of the Netherlands were liberated in 1945.

The Battle of France was the German invasion of France, Belgium, Luxembourg and the Netherlands during the Second World War. On 3 September 1939, France declared war on Germany following the German invasion of Poland. In early September 1939, France began the limited Saar Offensive and by mid-October had withdrawn to their start lines. German armies invaded Belgium, Luxembourg and the Netherlands on 10 May 1940. Italy entered the war on 10 June 1940 and attempted an invasion of France. France and the Low Countries were conquered, ending land operations on the Western Front until the Normandy landings on 6 June 1944.

German forces began Fall Rot ("Case Red") on 5 June 1940. The sixty remaining French divisions and the two British divisions in France made a determined stand on the Somme and Aisne but were defeated by the German combination of air superiority and armoured mobility. German armies outflanked the intact Maginot Line and pushed deep into France, occupying Paris unopposed on 14 June. After the flight of the French government and the collapse of the French Army, German commanders met with French officials on 18 June to negotiate an end to hostilities.

On 22 June 1940, the Second Armistice at Compiègne was signed by France and Germany. The neutral Vichy government led by Marshal Philippe Pétain replaced the Third Republic and German military occupation began along the French North Sea and Atlantic coasts and their hinterlands.

The Dunkirk evacuation, codenamed Operation Dynamo and also known as the Miracle of Dunkirk, or just Dunkirk, was the evacuation of Allied soldiers during the Second World War from the beaches and harbour of Dunkirk, in the north of France, between 26 May and 4 June 1940. The operation commenced after large numbers of Belgian, British, and French troops were cut off and surrounded by German troops during the six-week Battle of France. In a speech to the House of Commons, British Prime Minister Winston Churchill called this "a colossal military disaster", saying "the whole root and core and brain of the British Army" had been stranded at Dunkirk and seemed about to perish or be captured. In his "We shall fight on the beaches" speech on 4 June, he hailed their rescue as a "miracle of deliverance".

The Italian invasion of France (10–25 June 1940), also called the Battle of the Alps, was the first major Italian engagement of World War II and the last major engagement of the Battle of France.

The Italian entry into the war widened its scope considerably in Africa and the Mediterranean Sea. The goal of the Italian leader, Benito Mussolini, was the elimination of Anglo-French domination in the Mediterranean, the reclamation of historically Italian territory (Italia irredenta) and the expansion of Italian influence over the Balkans and in Africa. France and Britain tried during the 1930s to draw Mussolini away from an alliance with Germany but the rapid German successes from 1938 to 1940 made Italian intervention on the German side inevitable by May 1940.

Italy declared war on France and Britain on the evening of 10 June, to take effect just after midnight.

The Armistice of 22 June 1940 was signed at 18:36 near Compiègne, France, by officials of Nazi Germany and the Third French Republic. It did not come into effect until after midnight on 25 June. Signatories for Germany included Wilhelm Keitel, a senior military officer of the Wehrmacht (the German armed forces), while those on the French side held lower ranks including General Charles Huntziger. Following the decisive German victory in the Battle of France (10 May – 21 June 1940) during World War II, this armistice established a German occupation zone in Northern and Western France that encompassed all English Channel and Atlantic Ocean ports and left the remainder "free" to be governed by the French. Adolf Hitler deliberately chose Compiègne Forest as the site to sign the armistice due to its symbolic role as the site of the 1918 Armistice with Germany that signaled the end of World War I with Germany's surrender.

The Battle of Britain was a military campaign of the Second World War, in which the Royal Air Force (RAF) and the Fleet Air Arm (FAA) of the Royal Navy defended the United Kingdom against large-scale attacks by Nazi Germany's air force, the Luftwaffe. It has been described as the first major military campaign fought entirely by air forces.

The primary objective of the German forces was to compel Britain to agree to a negotiated peace settlement. In July 1940, the air and sea blockade began, with the Luftwaffe mainly targeting coastal-shipping convoys, as well as ports and shipping centres such as Portsmouth. On 1 August, the Luftwaffe was directed to achieve air superiority over the RAF, with the aim of incapacitating RAF Fighter Command; 12 days later, it shifted the attacks to RAF airfields and infrastructure. As the battle progressed, the Luftwaffe also targeted factories involved in aircraft production and strategic infrastructure. Eventually, it employed terror bombing on areas of political significance and on civilians.

The Tripartite Pact, also known as the Berlin Pact, was an agreement between Germany, Italy, and Japan signed in Berlin on 27 September 1940 by, respectively, Joachim von Ribbentrop, Galeazzo Ciano and Saburō Kurusu. It was a defensive military alliance that was eventually joined by Hungary (20 November 1940), Romania (23 November 1940), Bulgaria (1 March 1941) and Yugoslavia (25 March 1941) as well as by the German client state of Slovakia (24 November 1940). Yugoslavia's accession provoked a coup d'état in Belgrade two days later. Germany, Italy and Hungary responded by invading Yugoslavia. The resulting Italo-German client state, known as the Independent State of Croatia, joined the pact on 15 June 1941.

The Tripartite Pact was directed primarily at the United States. Its practical effects were limited since the Italo-German and Japanese operational theatres were on opposite sides of the world, and the high contracting powers had disparate strategic interests. As such the Axis was only ever a loose alliance. Its defensive clauses were never invoked, and signing the agreement did not oblige its signatories to fight a common war per se.

The Balkans campaign of World War II began with the Italian invasion of Greece on 28 October 1940. In the early months of 1941, Italy's offensive had stalled and a Greek counter-offensive pushed into Albania. Germany sought to aid Italy by deploying troops to Romania and Bulgaria and attacking Greece from the east. Meanwhile, the British landed troops and aircraft to shore up Greek defences. A coup d'état in Yugoslavia on 27 March caused Adolf Hitler to order the conquest of that country.

The invasion of Yugoslavia by Germany and Italy began on 6 April 1941, simultaneously with the new Battle of Greece; on 11 April, Hungary joined the invasion. By 17 April the Yugoslavs had signed an armistice, and by 30 April all of mainland Greece was under German or Italian control. On 20 May Germany invaded Crete by air, and by 1 June all remaining Greek and British forces on the island had surrendered. Although it had not participated in the attacks in April, Bulgaria occupied parts of both Yugoslavia and Greece shortly thereafter for the remainder of the war in the Balkans.

The Afrika Korps formed on 11 January 1941 and one of Hitler's favourite generals, Erwin Rommel, was designated as commander on 11 February. Originally Hans von Funck was to have commanded it, but Hitler loathed von Funck, as he had been a personal staff officer of Werner von Fritsch until von Fritsch was dismissed in 1938.

The German Armed Forces High Command (Oberkommando der Wehrmacht, OKW) had decided to send a "blocking force" to Italian Libya to support the Italian army. The Italian 10th Army had been routed by the British Commonwealth Western Desert Force in Operation Compass (9 December 1940 – 9 February 1941) and captured at the Battle of Beda Fomm.

The German invasion of Greece was the attack of Allied Greece by Fascist Italy and Nazi Germany during World War II. The Italian invasion in October 1940, which is usually known as the Greco-Italian War, was followed by the German invasion in April 1941. German landings on the island of Crete (May 1941) came after Allied forces had been defeated in mainland Greece. These battles were part of the greater Balkans Campaign of the Axis powers and their associates.

Following the Italian invasion on 28 October 1940, Greece, with British air and material support, repelled the initial Italian attack and a counter-attack in March 1941. When the German invasion, known as Operation Marita, began on 6 April, the bulk of the Greek Army was on the Greek border with Albania, then a vassal of Italy, from which the Italian troops had attacked. German troops invaded from Bulgaria, creating a second front. Greece received a small reinforcement from British, Australian and New Zealand forces in anticipation of the German attack. The Greek army found itself outnumbered in its effort to defend against both Italian and German troops. As a result, the Metaxas defensive line did not receive adequate troop reinforcements and was quickly overrun by the Germans, who then outflanked the Greek forces at the Albanian border, forcing their surrender. British, Australian and New Zealand forces were overwhelmed and forced to retreat, with the ultimate goal of evacuation. For several days, Allied troops played an important part in containing the German advance on the Thermopylae position, allowing ships to be prepared to evacuate the units defending Greece. The German Army reached the capital, Athens, on 27 April and Greece's southern shore on 30 April, capturing 7,000 British, Australian and New Zealand personnel and ending the battle with a decisive victory. The conquest of Greece was completed with the capture of Crete a month later. Following its fall, Greece was occupied by the military forces of Germany, Italy and Bulgaria.

Operation Barbarossa was the invasion of the Soviet Union by Nazi Germany and many of its Axis allies, starting on Sunday, 22 June 1941, during World War II. The operation, code-named after Frederick Barbarossa ("red beard"), a 12th-century Holy Roman emperor and German king, put into action Nazi Germany's ideological goal of conquering the western Soviet Union to repopulate it with Germans. The German Generalplan Ost aimed to use some of the conquered people as forced labour for the Axis war effort while acquiring the oil reserves of the Caucasus as well as the agricultural resources of various Soviet territories. Their ultimate goal was to create more Lebensraum (living space) for Germany, and the eventual extermination of the indigenous Slavic peoples by mass deportation to Siberia, Germanisation, enslavement, and genocide.

The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawaii, just before 8:00 a.m., on Sunday, December 7, 1941. The United States was a neutral country at the time; the attack led to its formal entry into World War II the next day. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning.

Japan intended the attack as a preventive action. Its aim was to prevent the United States Pacific Fleet from interfering with its planned military actions in Southeast Asia against overseas territories of the United Kingdom, the Netherlands, and those of the United States. Over the course of seven hours there were coordinated Japanese attacks on the US-held Philippines, Guam, and Wake Island and on the British Empire in Malaya, Singapore, and Hong Kong.

The attack commenced at 7:48 a.m. Hawaiian Time (6:18 p.m. GMT). The base was attacked by 353 Imperial Japanese aircraft (including fighters, level and dive bombers, and torpedo bombers) in two waves, launched from six aircraft carriers. Of the eight US Navy battleships present, all were damaged, with four sunk. All but USS Arizona were later raised, and six were returned to service and went on to fight in the war.

The Malayan campaign was a military campaign fought by Allied and Axis forces in Malaya, from 8 December 1941 – 15 February 1942 during the Second World War. It was dominated by land battles between British Commonwealth army units and the Imperial Japanese Army, with minor skirmishes at the beginning of the campaign between British Commonwealth and Royal Thai Police. The Japanese had air and naval supremacy from the opening days of the campaign. For the British, Indian, Australian, and Malayan forces defending the colony, the campaign was a total disaster.

The operation is notable for the Japanese use of bicycle infantry, which allowed troops to carry more equipment and swiftly move through thick jungle terrain. Royal Engineers, equipped with demolition charges, destroyed over a hundred bridges during the retreat, yet this did little to delay the Japanese. By the time the Japanese had captured Singapore, they had suffered 9,657 casualties; Allied losses totaled 145,703, including 15,703 casualties and 130,000 captured.

On December 8, 1941, the United States Congress declared war on the Empire of Japan in response to that country's surprise attack on Pearl Harbor and declaration of war the prior day. It was formulated an hour after the Infamy Speech of President Franklin D. Roosevelt. Following the U.S. declaration, Japan's allies, Germany and Italy, declared war on the United States, bringing the United States fully into World War II.

The Burma campaign was a series of battles fought in the British colony of Burma. It was part of the South-East Asian theatre of World War II and primarily involved forces of the Allies; the British Empire and the Republic of China, with support from the United States. They faced against the invading forces of Imperial Japan, who were supported by the Thai Phayap Army, as well as two collaborationist independence movements and armies, the first being the Burma Independence Army, which spearheaded the initial attacks against the country. Puppet states were established in the conquered areas and territories were annexed, while the international Allied force in British India launched several failed offensives. During the later 1944 offensive into India and subsequent Allied recapture of Burma the Indian National Army, led by revolutionary Subhas C. Bose and his "Free India", were also fighting together with Japan. British Empire forces peaked at around 1,000,000 land and air forces, and were drawn primarily from British India, with British Army forces (equivalent to eight regular infantry divisions and six tank regiments), 100,000 East and West African colonial troops, and smaller numbers of land and air forces from several other Dominions and Colonies.

The Fall of Singapore, also known as the Battle of Singapore, took place in the South–East Asian theatre of the Pacific War. The Empire of Japan captured the British stronghold of Singapore, with fighting lasting from 8 to 15 February 1942. Singapore was the foremost British military base and economic port in South–East Asia and had been of great importance to British interwar defence strategy. The capture of Singapore resulted in the largest British surrender in its history. Prior to the battle, Japanese General Tomoyuki Yamashita had advanced with about 30,000 men down the Malayan Peninsula in the Malayan campaign. The British erroneously considered the jungle terrain impassable, leading to a swift Japanese advance as Allied defences were quickly outflanked. The British Lieutenant-General, Arthur Percival, commanded 85,000 Allied troops at Singapore, although many units were under-strength and most units lacked experience. The British outnumbered the Japanese but much of the water for the island was drawn from reservoirs on the mainland. The British destroyed the causeway, forcing the Japanese into an improvised crossing of the Johore Strait. Singapore was considered so important that Prime Minister Winston Churchill ordered Percival to fight to the last man.

The Battle of the Coral Sea, from 4 to 8 May 1942, was a major naval battle between the Imperial Japanese Navy (IJN) and naval and air forces of the United States and Australia. Taking place in the Pacific Theatre of World War II, the battle is historically significant as the first action in which the opposing fleets neither sighted nor fired upon one another, attacking over the horizon with aircraft carriers instead.

Although the battle was a tactical victory for the Japanese in terms of ships sunk, it has been described as a strategic victory for the Allies. The battle marked the first time since the start of the war that a major Japanese advance had been turned back.

The Battle of Midway was a major naval battle in the Pacific Theater of World War II that took place on 4–7 June 1942, six months after Japan's attack on Pearl Harbor and one month after the Battle of the Coral Sea. The U.S. Navy under Admirals Chester W. Nimitz, Frank J. Fletcher, and Raymond A. Spruance defeated an attacking fleet of the Imperial Japanese Navy under Admirals Isoroku Yamamoto, Chūichi Nagumo, and Nobutake Kondō north of Midway Atoll, inflicting devastating damage on the Japanese fleet. Military historian John Keegan called it "the most stunning and decisive blow in the history of naval warfare", while naval historian Craig Symonds called it "one of the most consequential naval engagements in world history, ranking alongside Salamis, Trafalgar, and Tsushima Strait, as both tactically decisive and strategically influential".

Luring the American aircraft carriers into a trap and occupying Midway was part of an overall "barrier" strategy to extend Japan's defensive perimeter, in response to the Doolittle air raid on Tokyo. This operation was also considered preparatory for further attacks against Fiji, Samoa, and Hawaii itself. The plan was undermined by faulty Japanese assumptions of the American reaction and poor initial dispositions. Most significantly, American cryptographers were able to determine the date and location of the planned attack, enabling the forewarned U.S. Navy to prepare its own ambush.

Four Japanese and three American aircraft carriers participated in the battle. The four Japanese fleet carriers—Akagi, Kaga, Sōryū, and Hiryū, part of the six-carrier force that had attacked Pearl Harbor six months earlier—were sunk, as was the heavy cruiser Mikuma. The U.S. lost the carrier Yorktown and the destroyer Hammann, while the carriers USS Enterprise and USS Hornet survived the battle fully intact.

After Midway and the exhausting attrition of the Solomon Islands campaign, Japan's capacity to replace its losses in materiel (particularly aircraft carriers) and men (especially well-trained pilots and maintenance crewmen) rapidly became insufficient to cope with mounting casualties, while the United States' massive industrial and training capabilities made losses far easier to replace. The Battle of Midway, along with the Guadalcanal campaign, is widely considered a turning point in the Pacific War.

The Battle of Stalingrad (23 August 1942 – 2 February 1943) was a major battle on the Eastern Front of World War II where Nazi Germany and its allies unsuccessfully fought the Soviet Union for control of the city of Stalingrad (later renamed to Volgograd) in Southern Russia. The battle was marked by fierce close-quarters combat and direct assaults on civilians in air raids, with the battle being the epitome of urban warfare. The Battle of Stalingrad was the deadliest battle to take place during the Second World War and is one of the bloodiest battles in the history of warfare, with an estimated 2 million total casualties. Today, the Battle of Stalingrad is universally regarded as the turning point in the European Theatre of war, as it forced the Oberkommando der Wehrmacht (German High Command) to withdraw considerable military forces from other areas in occupied Europe to replace German losses on the Eastern Front. The victory at Stalingrad energized the Red Army and shifted the balance of power in the favour of the Soviets.

Stalingrad was strategically important to both sides as a major industrial and transport hub on the Volga River. Whoever controlled Stalingrad would have access to the oil fields of the Caucasus; and control of the Volga. Germany, already operating on dwindling fuel supplies focused its efforts on moving deeper into Soviet territory and taking the oil fields at any cost. On 4 August, the Germans launched an offensive by using the 6th Army and elements of the 4th Panzer Army. The attack was supported by intense Luftwaffe bombing that reduced much of the city to rubble. The battle degenerated into house-to-house fighting as both sides poured reinforcements into the city. By mid-November, the Germans, at great cost, had pushed the Soviet defenders back into narrow zones along the west bank of the river.

On 19 November, the Red Army launched Operation Uranus, a two-pronged attack targeting the Romanian armies protecting the 6th Army's flanks. The Axis flanks were overrun and the 6th Army was cut off and surrounded in the Stalingrad area. Adolf Hitler was determined to hold the city at all costs and forbade the 6th Army from attempting a breakout; instead, attempts were made to supply it by air and to break the encirclement from the outside. The Soviets were successful in denying the Germans the ability to resupply through the air which strained the German forces to their breaking point. Nevertheless, the German forces were determined to continue their advance and heavy fighting continued for another two months. On 2 February 1943, the German 6th army, having exhausted their ammunition and food, finally capitulated, making it the first of Hitler's field armies to surrender during World War II, after five months, one week, and three days of fighting.

The Second Battle of El Alamein (23 October – 11 November 1942) was a battle of the Second World War that took place near the Egyptian railway halt of El Alamein. The First Battle of El Alamein and the Battle of Alam el Halfa had prevented the Axis from advancing further into Egypt.

In August 1942, General Claude Auchinleck had been relieved as Commander-in-Chief Middle East Command and his successor, Lieutenant-General William Gott was killed on his way to replace him as commander of the Eighth Army. Lieutenant-General Bernard Montgomery was appointed and led the Eighth Army offensive.

The British victory was the beginning of the end of the Western Desert Campaign, eliminating the Axis threat to Egypt, the Suez Canal and the Middle Eastern and Persian oil fields. The battle revived the morale of the Allies, being the first big success against the Axis since Operation Crusader in late 1941. The end of the battle coincided with the Allied invasion of French North Africa in Operation Torch on 8 November, which opened a second front in North Africa.

Operation Torch (8 November 1942 – 16 November 1942) was an Allied invasion of French North Africa during the Second World War. Torch was a compromise operation that met the British objective of securing victory in North Africa while allowing American armed forces the opportunity to engage in the fight against Nazi Germany on a limited scale. It was the first mass involvement of US troops in the European–North African Theatre, and saw the first major airborne assault carried out by the United States.

The Western Task Force encountered unexpected resistance and bad weather, but Casablanca, the principal French Atlantic naval base, was captured after a short siege. The Center Task Force suffered some damage to its ships when trying to land in shallow water but the French ships were sunk or driven off; Oran surrendered after bombardment by British battleships. The French Resistance had unsuccessfully attempted a coup in Algiers and, even though this raised alertness in the Vichy forces, the Eastern Task Force met less opposition and were able to push inland and compel surrender on the first day.

The success of Torch caused Admiral François Darlan, commander of the Vichy French forces, to order co-operation with the Allies, in return for being installed as High Commissioner, with many other Vichy officials keeping their jobs.

Operation Husky was a major campaign of World War II in which the Allies invaded the island of Sicily and took it from the Axis powers (Fascist Italy and Nazi Germany). It began with a large amphibious and airborne operation, followed by a six-week land campaign, and initiated the Italian Campaign.

To divert some of the Axis forces to other areas, the Allies engaged in several deception operations, the most famous and successful of which was Operation Mincemeat. Husky began on the night of 9–10 July 1943, and ended on 17 August. Strategically, Husky achieved the goals set out for it by Allied planners; the Allies drove Axis air, land and naval forces from the island and the Mediterranean sea lanes were opened for Allied merchant ships for the first time since 1941. These events led to the Italian leader, Benito Mussolini, being toppled from power in Italy on 25 July, and to the Allied invasion of Italy on 3 September.

The German leader, Adolf Hitler, "canceled a major offensive at Kursk after only a week, in part to divert forces to Italy," resulting in a reduction of German strength on the Eastern Front. The collapse of Italy necessitated German troops replacing the Italians in Italy and to a lesser extent the Balkans, resulting in one fifth of the entire German army being diverted from the east to southern Europe, a proportion that would remain until near the end of the war.

The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as D-Day, it was the largest seaborne invasion in history. The operation began the liberation of France (and later western Europe) and laid the foundations of the Allied victory on the Western Front.

The amphibious landings were preceded by extensive aerial and naval bombardment and an airborne assault—the landing of 24,000 American, British, and Canadian airborne troops shortly after midnight. Allied infantry and armoured divisions began landing on the coast of France at 06:30. The target 50-mile (80 km) stretch of the Normandy coast was divided into five sectors: Utah, Omaha, Gold, Juno, and Sword. Strong winds blew the landing craft east of their intended positions, particularly at Utah and Omaha. The men landed under heavy fire from gun emplacements overlooking the beaches, and the shore was mined and covered with obstacles such as wooden stakes, metal tripods, and barbed wire, making the work of the beach-clearing teams difficult and dangerous. Casualties were heaviest at Omaha, with its high cliffs. At Gold, Juno, and Sword, several fortified towns were cleared in house-to-house fighting, and two major gun emplacements at Gold were disabled using specialised tanks.

The Allies failed to achieve any of their goals on the first day. Carentan, Saint-Lô, and Bayeux remained in German hands, and Caen, a major objective, was not captured until 21 July. Only two of the beaches (Juno and Gold) were linked on the first day, and all five beachheads were not connected until 12 June; however, the operation gained a foothold that the Allies gradually expanded over the coming months. German casualties on D-Day have been estimated at 4,000 to 9,000 men. Allied casualties were documented for at least 10,000, with 4,414 confirmed dead. Museums, memorials, and war cemeteries in the area now host many visitors each year.

The liberation of Paris was a military battle that took place during World War II from 19 August 1944 until the German garrison surrendered the French capital on 25 August 1944. Paris had been occupied by Nazi Germany since the signing of the Second Compiègne Armistice on 22 June 1940, after which the Wehrmacht occupied northern and western France.

The liberation began when the French Forces of the Interior—the military structure of the French Resistance—staged an uprising against the German garrison upon the approach of the US Third Army, led by General George Patton. On the night of 24 August, elements of General Philippe Leclerc's 2nd French Armored Division made their way into Paris and arrived at the Hôtel de Ville shortly before midnight. The next morning, 25 August, the bulk of the 2nd Armored Division and US 4th Infantry Division and other allied units entered the city. Dietrich von Choltitz, commander of the German garrison and the military governor of Paris, surrendered to the French at the Hôtel Le Meurice, the newly established French headquarters. General Charles de Gaulle of the French Army arrived to assume control of the city as head of the Provisional Government of the French Republic.

The Allied advance from Paris to the Rhine was a phase in the Western European campaign of World War II. This phase spans from the end of the Battle of Normandy, or Operation Overlord, (25 August 1944) incorporating the German winter counter-offensive through the Ardennes (commonly known as the Battle of the Bulge) and Operation Nordwind (in Alsace and Lorraine) up to the Allies preparing to cross the Rhine in the early months of 1945.

After Hitler's 29 August 1944 declaration to begin V-2 attacks as soon as possible, the offensive began on 7 September 1944 when two were launched at Paris (which the Allies had liberated less than two weeks earlier), but both crashed soon after launch. On 8 September a single rocket was launched at Paris, which caused modest damage near Porte d'Italie., 467 Two more launches by the 485th followed, including one from The Hague against London on the same day at 6:43 pm. – the first landed at Staveley Road, Chiswick, killing 63-year-old Mrs.

The British government initially attempted to conceal the cause of the explosions by blaming them on defective gas mains. The public therefore began referring to the V-2s as "flying gas pipes". The Germans themselves finally announced the V-2 on 8 November 1944 and only then, on 10 November 1944, did Winston Churchill inform Parliament, and the world, that England had been under rocket attack "for the last few weeks". Because of their inaccuracy, these V-2s did not hit their target cities. Shortly after that only London and Antwerp remained as designated targets as ordered by Adolf Hitler himself, Antwerp being targeted in the period of 12 to 20 October, after which time the unit moved to The Hague.

The final two rockets exploded on 27 March 1945. One of these was the last V-2 to kill a British civilian and the final civilian casualty of the war on British soil: Ivy Millichamp, aged 34, killed in her home in Kynaston Road, Orpington in Kent.

The Battle of the Bulge, also known as the Ardennes Offensive, was the last major German offensive campaign on the Western Front during World War II. The offensive was carried out from 16 December 1944 to 25 January 1945, towards the end of the war in Europe. It was launched through the densely forested Ardennes region between Belgium and Luxembourg.

The primary military objectives were to deny further use of the Belgian port of Antwerp to the Allies and to split the Allied lines, which potentially could have allowed the Germans to encircle and destroy the four Allied forces. Nazi dictator Adolf Hitler, who by this time had assumed direct command of the German armed forces, believed that achieving these objectives would compel the Western Allies to accept a peace treaty in the Axis powers' favor. By this time, it was palpable to virtually the entire German leadership including Hitler himself that they had no realistic hope of repelling the imminent Soviet invasion of Germany unless the Wehrmacht was able to concentrate the entirety of its remaining forces on the Eastern Front, which in turn obviously required that hostilities on the Western and Italian Fronts be terminated. The Battle of the Bulge remains among the most important battles of the war, as it marked the last major offensive attempted by the Axis Powers on the Western front. After their defeat, Germany would retreat for the remainder of the war.

The German Instrument of Surrender was the legal document that effected the unconditional surrender of Nazi Germany and ended World War II in Europe. The decision to surrender was made public on 8 May 1945. The definitive text was signed in Karlshorst, Berlin, on the night of 8 May 1945 by representatives of the three armed services of the Oberkommando der Wehrmacht (OKW) and the Allied Expeditionary Force together with the Supreme High Command of the Soviet Red Army, with further French and US representatives signing as witnesses. The signing took place 9 May 1945 at 00:16 local time.

The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the only use of nuclear weapons in armed conflict.

The consent of the United Kingdom was obtained for the bombing, as was required by the Quebec Agreement, and orders were issued on 25 July by General Thomas Handy, the acting Chief of Staff of the United States Army, for atomic bombs to be used against Hiroshima, Kokura, Niigata, and Nagasaki. On 6 August, a Little Boy was dropped on Hiroshima, to which Prime Minister Suzuki reiterated the Japanese government's commitment to ignore the Allies' demands and fight on. Three days later, a Fat Man was dropped on Nagasaki. Over the next two to four months, the effects of the atomic bombings killed between 90,000 and 146,000 people in Hiroshima and 39,000 and 80,000 people in Nagasaki; roughly half occurred on the first day. For months afterward, many people continued to die from the effects of burns, radiation sickness, and injuries, compounded by illness and malnutrition. Though Hiroshima had a sizable military garrison, most of the dead were civilians.

Aircraft were used for reconnaissance, as fighters, bombers, and ground-support, and each role was advanced considerably. Innovation included airlift (the capability to quickly move limited high-priority supplies, equipment, and personnel); and of strategic bombing (the bombing of enemy industrial and population centres to destroy the enemy's ability to wage war). The use of the jet aircraft was pioneered and, though late introduction meant it had little impact, it led to jets becoming standard in air forces worldwide.

Advances were made in nearly every aspect of naval warfare, most notably with aircraft carriers and submarines. Although aeronautical warfare had relatively little success at the start of the war, actions at Taranto, Pearl Harbor, and the Coral Sea established the carrier as the dominant capital ship in place of the battleship. Submarines, which had proved to be an effective weapon during the First World War, were anticipated by all sides to be important in the second. The British focused development on anti-submarine weaponry and tactics, such as sonar and convoys, while Germany focused on improving its offensive capability, with designs such as the Type VII submarine and wolfpack tactics. Gradually, improving Allied technologies such as the Leigh light, hedgehog, squid, and homing torpedoes proved victorious over the German submarines.

Land warfare changed from the static front lines of trench warfare of World War I, which had relied on improved artillery that outmatched the speed of both infantry and cavalry, to increased mobility and combined arms. The tank, which had been used predominantly for infantry support in the First World War, had evolved into the primary weapon.

Most major belligerents attempted to solve the problems of complexity and security involved in using large codebooks for cryptography by designing ciphering machines, the most well known being the German Enigma machine. Development of SIGINT (signals intelligence) and cryptanalysis enabled the countering process of decryption.

Other technological and engineering feats achieved during, or as a result of, the war include the world's first programmable computers (Z3, Colossus, and ENIAC), guided missiles and modern rockets, the Manhattan Project's development of nuclear weapons, operations research and the development of artificial harbours and oil pipelines under the English Channel. Penicillin was first mass-produced and used during the war.