There are several places you can rappel in Bonito [1] (including the Buraco das Araras [2] and the Boca da Onça), but the most breathtaking option is to go to the Abismo Anhumas (Estrada Campo dos Índios, Fazenda Anhumas, 22 kilometers from Bonito). If you’ve never rappelled before, this is the perfect initiation.
After monitors teach you the ropes, you’ll get geared up and then plunge 72 meters (236 feet) into an abyss studded with stalactites and stalagmites. At the bottom is a lagoon the size of a soccer field where you can snorkel. Rappelling and snorkeling costs R$360. Reserve in advance.
Links:
[1] http://www.moon.com/destinations/brazil/brasilia-and-the-pantanal/the-pantanal/bonito
[2] http://www.moon.com/destinations/brazil/brasilia-and-the-pantanal/the-pantanal/bonito/sights