Cave diver Dave Bunnel, 61, captured these stunning images of him diving into Mexico’s El Sotano de las Golodrinas, The Basement of Swallows — - a 1,200-foot-deep hole in Mexico that is so deep, clouds form inside. The pit was first descended in December of 1967 by a trio of Americans. Its total depth is 1,638ft although the final few hundred feet accessible are only accessible through a pit series called The Crevice. It gets its name, the Basement of Swallows, thanks to the birds that fly above its opening.
Photo credit: Dave Bunnel