Oaxaca (pronounced Wo-haka) is situated in the central highlands. The region was originally settled in pre-Columbian times by the Zapotecs and later the Mixotecs and is home to their ancient ruins at Monte Alban and Milta.
Read more on the (Wiki link).
Oaxaca Cultural Museum

Conquistador armour

Gold breast plate recovered from Monte Alban's Mixotec burial at Tomb No.7

The Cathedral of Our Lady of the Assumption in the main plaza
The Oldest tree in the Americas - the Tule Tree