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.
Vikos Gorge
The Vikos Gorge, with a length of , walls that range from deep, and a width ranging from to just a few meters at its narrowest part, is listed by the Guinness Book of Records as the deepest canyon in the world in proportion to its width, though some gorge lobbyists contest that claim. The main part of the gorge stretches from the village of Vikos to Monodendri, and attains a depth of about .