The Maya, an ancient South American culture, predicted that time would end in a violent apocalypse on December 21, 2012. They created an elaborate astronomical calendar called “The Long Count,” which stops abruptly in 2012. This date, which is also the winter equinox, coincides with an incredibly rare galactic alignment that happens once every 26,000 years. What did the Mayans think would happen when their calendar ended? And were they joined by other cultures–from different parts of the world and in different centuries–all pointing to 2012 as a calamitous end time?