Abismo Guy Collet
The Abismo Guy Collet (SP-090) is the deepest cave in South America, and the deepest in the world that is formed in quartzite. Located in a tepui in northern Brazil near the border with Venezuela, this cave was first explored by cavers in 2006 to a depth of 671 meters.
GB Cave
GB Cave is a cave between Charterhouse and Shipham in the limestone of the Mendip Hills, in Somerset, England, and is close to Charterhouse Cave, the deepest in the region.