Snorkeling in Parque Nacional da Chapada dos Guimarães
A steep scramble takes you to a viewpoint overlooking the lush valley and the razor-thin rock formations of the Crista do Galo (rooster's crest). Then you swim and snorkel in clear, deep, rapid-fed pools in the forest before embarking on a 500m float, following your guide along the twists and turns of the narrow river, the somber underwater world revealing itself beneath you.
You need to go with a registered guide. If you don't have a 4x4, you'd better contract a guide that does.