▸ According to their calendar, the first day of the world was August 11, 3114 BC and the last date is December 21, 2012. This is the fact that fueled doomsday conspiracy theories. Fortunately, the Mayans built their calendars in a circular fashion, that meant that the calendar started over again, a detail that the conspiracy theorists conveniently oversaw. Also, the starting date indicates that they did not believe in evolution or dinosaurs.