Mayan ruins at Chichén Itzá, Yucatan, Mexico.

Maya ruins at Chichén Itzá, Yucatan, Mexico. 
Top, from left to right: The Great Ball Court was used for sporting events and, at 146-meters (480-feet) long, it is the largest court in Mesoamerica.
The Temple of Kukulan was built for astronomical purposes.
The Temple of the Warriors was built for large gatherings.
 In the foreground: El Caracol (Spanish for snail) is a rounded structure and possible observatory as it aligns with Venus.