Anhumas Abyss is a cave 23km from the city of Bonito Mato Grosso do Sul, Brazil. Access is by a gap that exists in the Rock through vertical Rappelling techniques. To the base of the cave is 72 meters of vertical drop, until the deck on the lake of clear water. That can reach 80m. depth. During some days of the year the sun passes through the small opening of the cave, producing a beam of light that illuminates the cave for a few hours.