The Mayans were an advanced civilization in Mexico and Belize dating back to 1800 BCE. They had sophisticated architecture, agriculture, and many gods they worshipped through human sacrifice. The Mayans peaked around 250 AD with many city-states vying for power. While they had a developed calendar, writing system, and astronomical understanding, Spanish conquistador Hernando Cortes conquered the Mayans in the 1500s, greatly reducing their population through warfare, disease, and slavery. Today around 6 million people can trace their descent from the Mayans and still practice aspects of the traditional culture.