On the night of July 29, the 15-meter-high (roughly 50-foot-high) square monument located in the state of Michoacán suddenly slumped under the pressure of incessant rain, its south wall crumbling into a pile of rubble.

The pyramid was once one of the best-preserved monuments of the Michoacán Kingdom civilization. It is located at Ihuatzio, a remarkably preserved archaeological site that contains one other pyramid, a tower or fortress, and some tombs.

Only one of the pyramids at the site was damaged, but personnel from Mexico’s National Institute of Anthropology and History (INAH) said that at least six of its ‘stepped bodies’ are in disrepair, including the outer wall, and the core and retaining wall.

They blamed extreme weather preceding the event.