The September 11 attacks were a series of terrorist attacks carried out by the Islamic extremist group al-Qaeda on September 11, 2001. Four coordinated attacks were launched in the United States that day, with the goal of destroying symbolic and military targets. The attacks resulted in the deaths of 2,977 people, as well as significant destruction of property and infrastructure.

The first two attacks involved the hijacking and crashing of American Airlines Flight 11 and United Airlines Flight 175 into the North and South towers, respectively, of the World Trade Center complex in New York City. Both towers collapsed within hours, causing widespread destruction and fatalities.

The third attack targeted the Pentagon in Arlington, Virginia, just outside of Washington, D.C. American Airlines Flight 77 was hijacked and flown into the building, causing significant damage and loss of life.

The fourth and final attack of the day targeted either the White House or the U.S. Capitol Building, but the hijackers of United Airlines Flight 93 were ultimately thwarted by passengers, who attempted to overcome the hijackers and regain control of the plane. The plane crashed into a field near Shanksville, Pennsylvania, killing all on board.

The attacks were planned and executed by al-Qaeda, a terrorist organization that was led by Osama bin Laden. The group had previously carried out other attacks, including the 1998 U.S. embassy bombings in Kenya and Tanzania, but the September 11 attacks were by far the most devastating. The United States and its allies responded to the attacks with a series of military and diplomatic initiatives, including the U.S. invasion of Afghanistan to topple the Taliban regime, which had harbored al-Qaeda and other terrorist groups.

The 9/11 attacks has affected the entire world and it was considered as a turning point for USA and lead to many political and social changes. The attacks, and the broader War on Terror that followed, continue to shape international relations and domestic policies to this day.