This large (9940 sq km) Amazonian rain-forest national park lies west of the town of Itaituba (population 65,000), which is 250km southwest of Santarém. To visit, you must obtain prior permission from the IBAMA office and an IBAMA staff member must accompany you on your visit. It is possible to stay at rudimentary facilities at an IBAMA post inside the park, but there’s no real visitor infrastructure here. Alternatively, ask at Mãe Natureza, Areia Branca Ecotour or Gil Serique both in Alter de Chão, about arranging a trip there.