Encompassing much of the Serra da Bocaina, the Parque Nacional da Serra da Bocaina (Estrada da Bocaina Km 27, tel. 12/3117-2183) spans the states of São Paulo  and Rio de Janeiro , embracing the coastal towns of Angra , Paraty , and Ubatuba .
Although access is difficult (you need a four-wheel-drive) and infrastructure is virtually nonexistent, this national park offers over 100,000 hectares (250,000 acres) of virgin Atlantic forest brimming with wild orchids, hortensias, and bromeliads, dozens of waterfalls, and the chance of catching a glimpse of rare beasts such as the spotted jaguar and mono-carvoeiro monkey.
The best way to visit Parque Nacional da Serra da Bocaina is by guided tour. In São José, MW Trekking (Praça Coronel Cunha Lana, tel. 12/3117-1220, www.mwtrekking.com.br ) offers day trips that include hiking, with stops for lunch and bathing in waterfalls. For more intrepid souls, the company offers a three-day trek that follows the Trilha do Ouro over the hills to the Praia de Mambucaba, a gorgeous beach located between Paraty  and Angra . In the 18th century, slaves laid the massive stones (many of which still exist) of this trail.
The route was used by tropeiros to carry precious gold, and later coffee, down to the coast, where it could be shipped off to Europe. This R$560 excursion includes food and lodgings supplied by locals who offer rooms in their simple homes (without electricity) as well as home-cooked meals prepared in wood-burning ovens.