Cave of Swallows

The Cave of Swallows (Spanish: Sótano de las Golondrinas), is an open air pit cave in the Municipality of Aquismon, San Luis Potosi, Mexico. The elliptical mouth, on a slope of karst, is 49x62 m wide and is undercut around all its perimeter, further widening to a room approximately 303x135 meters wide. The floor of the cave is a 333 meter freefall drop from the lowest side of the opening, with a 370 meter drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest in the world. A skyscraper such as the Chrysler Building could easily fit wholly within it.