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.
Bill Steele (cave explorer)
Continuing to explore caves throughout the United States, Steele led and participated in expeditions to Sistema Huautla in Mexico almost every year through the 1980s. In 1987, the Huautla expedition connected the deep cave Nita Nanta to Sistema Huautla; which established it as the second deepest cave in the world. Steele went to Kijahe Xontjoa on the plateau to the east of Huautla with an expedition of Swiss explorers in 1993, and explored depths over 1,000 meters.