Amid spectacular natural wonders, Bonito is a small, charming town in southwest Mato Grosso do Sul that is enjoying the ecotourism boom. Most travelers go there to snorkel down crystal-clear rivers, but there are dozens of other ways to enjoy the scenery, from rappelling and rafting to horseback riding and bird-watching. Despite its popularity, the town is still a great place to kick back outside peak holiday periods (December to February). 
One of the best rivers for snorkeling is the Rio da Prata(5hr trip incl lunch US$46), some 50km from Bonito; the trip includes a short hike through rainforest, followed by 3km swim among 30 varieties of fish while floating gently downstream. There’s also the crystal-clear Rio Sucuri(3hr trip US$37) 20km from Bonito and the Aquário Natural Baía Bonita(3hr trip US$37), 7km from Bonito.
The Gruta do Lago Azul (half-day excursion US$12), 20km from Bonito, is a large cave, with a luminous underground lake and stalactites. The Balneário Municipal (admission US$5), 7km from Bonito, is a natural swimming pool with lots of fish (and no guide needed, easily reached by mototaxi or by bicycle). The Abismo de Anhumas (full-day excursion including rappelling and snorkeling US$120), 22km from Bonito, is a 72m abyss with an underground lake and incredible stalactites.
Read more: http://www.lonelyplanet.com/brazil/the-central-west/bonito#ixzz2Le3CvNVl
Also: The Daily Green
