Calakmul

Calakmul, an important Maya site set deep in the tropical forest of the Tierras Bajas in the state of Campeche, played a key role in the history of this region for more than twelve centuries. It's imposing structures and its characteristics overall layout are remarkably well-preserved and give a vivid picture of life in an ancient Mayan capital.

The archaeological site of Calakmul has the World Heritage status of the UNESCO since 2002.

source: Wikipedia