Update: photos show one of the largest tombs ever discovered in Mexico

A view of a burial chamber at the archeological site of Atzompa.

A view of the building (top) where archeologists found a burial chamber at the archeological site of Atzompa.

An archeologist brushes off dust at a burial chamber at the archeological site of Atzompa.

Archeologists work at the entrance of a burial chamber at the archeological site of Atzompa. More.