Gruta do Lago Azul

Gruta do Lago Azul (Blue Lake Cave) in Bonito, Brazil has a depth of nearly 100 meters. At the bottom lies what appears to be a bright blue lake, but it is in fact an underground river that flows through a series of interconnecting subterranean caves. A relatively recent dive uncovered fossils from sabre tooth tiger! The picture on the right shows a giant and rather unusual stalagmite formation.