In the Pre-Columbian Americas, the Maya civilization that flourished in Mexico and Central America during the 1st millennium CE developed a unique tradition of mathematics that, due to its geographic isolation, was entirely independent of existing European, Egyptian, and Asian mathematics.^[92] Maya numerals used a base of twenty, the vigesimal system, instead of a base of ten that forms the basis of the decimal system used by most modern cultures.^[92] The Maya used mathematics to create the Maya calendar as well as to predict astronomical phenomena in their native Maya astronomy.^[92] While the concept of zero had to be inferred in the mathematics of many contemporary cultures, the Maya developed a standard symbol for it.^[92]