Chichen Itza Mayan Ruins
Chichen Itza was originally a pure Mayan city. The Mayans abandoned the city sometime during the 9th Century AD. The Itzaes, a different group of Mayas settled in the city during the late 10th Century AD. The Toltecs then invaded Chichen Itza at some point. So the city has different architectural styles: the Puuc style (Red House, Temple of the Deer, and the Nunnery Complex) from the Uxmal/western Yucatan area; the Itza style (not sure where that is), and the Toltec style (Pyramid of Kukulcan, Temple of the Warriors, the Great Ball Court, and the Ossuary/Pyramid of the High Priest, and "Old" Chichen Itza which is currently not open to the public) for which Chichen Itza is most well known.
Chichen Itza was abandoned around 1200AD.
Map of Chichen Itza:
Click on image to enlarge: