Gruta dos Ecos (Lago dos Ecos)

The first reports of the cave date from 1973, and on 17 March 1975 it was explored as far as the shores of the inner lake. Already known to local residents, the cave was introduced to speleologists in 1976. Lago dos Ecos is about 300 m long and 50 m wide, with a length of 350 m also on record, and is described as the largest underground lake in South America. Located on private property, the cave saw intense tourist use until the early 2000s, which was suspended in 2001 after complaints by speleologists. Visits tend to be advised for the dry season, since during the rains there is a risk of rockfalls.