Calakmul (aka Kalakmul) is also the name given to site of one of the largest ancient Maya cities ever uncovered. It is located in the acre Calakmul Biosphere Reserve, deep in the jungles of the Peten, 30 km from the Guatemalan border.
El Tajín is a pre-Columbian archeological site and one of the largest and most important cities of the Classic era of Mesoamerica. A part of the Classic Veracruz culture, El Tajín flourished from 600 to 1200 AD
Image : Climbers at the bottom of the Golondrinas cave in Aquismon Region, Mexico. The towering walls of rock range from 325 feet tall to the deepest open-air pit in the world, Sotano de las Golondrinas (Cave of Swallows), which is over 1000 feet deep.