Original: Postclassic Era 900 1697 CE Collapse of many of the great nations and cities of the Classic Era , although some continue , such as in Oaxaca , Cholula , and the Maya of Yucatán , such as at Chichen Itza and Uxmal .
Simplified: Many of the great nations and cities of the Classic Era collapsed , but some continue , such as in Oaxaca , Cholula , and the Maya of Yucatán , such as at Chichen Itza and Uxmal .