The Chichen Itza Ruins

The Mayan Chichen Itza ruins are incredible as attested to by the 60,000 some odd peoplle who converge on this ruin site twice a year on the equinoxes to see the famous descending serpent illusion. Even more impressive is, according to the
official Chichen Itza website, this illusion was not present when the site the built but only occurs for an 80 year period, from 40 years prior to 2012 to 40 years after 2012. Chichen Itza tours take place in Mexico's state of Quintana Roo.