Gruta do Lago Azul Natural Monument
The Blue Lake Cave (Gruta do Lago Azul Natural Monument) is a natural monument near Bonito, Mato Grosso do Sul, Brazil. It has been designated as a protected area since 1978 and contains two caverns with remarkable but fragile calcareous structures. The main chamber of the Gruta do Lago Azul has a floor that falls down to an underground lake that is 50 meters (160 feet) long.
The entrance is circular, about 40 meters (130 feet) in diameter, and it shines brightly on the lake. The waters of the lake take on a striking blue tint between September and February, for which it is named. Large mammals that lived in the area for more than 12,000 years during the Pleistocene epoch have been discovered in the form of fossil bones. Giant sloths, armadillos and sabre-toothed tigers are among them.
The National Institute of Historic and Artistic Heritage designated the Gruta do Lago Azul and the Grutas de Nossa Senhora Aparecida, both near Bonito, Mato Grosso do Sul, as natural monuments in 1978. (IPHAN). The goal is to protect the cave's extremely delicate calcareous structures, the lake and its aquatic life, and the surrounding terrain. Visitors are welcome, as long as they are escorted by guides from the Bonito municipality. Regulations are in place to ensure that the cave is not harmed.
Location: near Bonito, Mato Grosso do Sul
