Sima de las Cotorras, Spanish for Sinkhole of Parrots, is a giant circular sinkhole in the karst plateau of the Mexican state of Chiapas. It measures 160 metres (520 ft) in diameter and 140 metres (460 ft) in depth, and is noted for the thousands of green parakeets inhabiting the trees at its bottom and the ancient paintings on its cliff wall 70 metres (230 ft) underground.^[2][3]

• http://en.wikipedia.org/wiki/Sima de las Cotorras