Near the town of Diamantina is a strange old rock formation used in a movie about Xica da Silva. The famous Xica was a slave during the diamond rush times. She persuaded her owner to build her a lake and a boat on the lake for her pleasure. Inside the strange rock formation is a cave, Gruta de Salitre, important in the movie rituals.
This view is from inside the cave looking at the back of the island of rocks of the previous photo.