The Sima de San Pedro is located in Spain, in the autonomous community of Aragon, a region characterized by aridity and extreme temperatures. It is a karst sinkhole, with a mouth of about 100 meters in diameter and a depth of 108, considered unique in Europe for its structure of exceptional geological value. At the bottom of the pit there is a 22-metre-deep lake containing 560,000 cubic metres of water.
Of karstic origin, it constitutes a real oasis in an arid territory, a proper ecosystem with more than 25 species of vertebrates, among which important colonies of bats.
