The Mayans were a dominant indigenous civilization in Mesoamerica from 1800 BC to AD 250 that excelled in agriculture, writing, calendar making, and mathematics. They built large urban centers like Tikal with temples, palaces, and ball courts of religious and political significance. The Mayans developed an advanced hieroglyphic writing system and the only fully developed calendar in the ancient Americas using the concept of zero. While their civilization declined gradually after AD 250 due to overtaxed resources and political instability, elements of Mayan culture still survive today.