Santarém is a terrific destination, a languid riverside town with a breezy waterfront promenade, parks, and several good restaurants. More than that, it's a fine gateway to several quintessential Amazon experiences – getting to primary rainforest, in the Floresta Nacional (FLONA) do Tapajós, is much easier here than from Manaus, and Santarém has it's very own 'meeting of the waters,' where the Rio Tapajós flows into the Amazon. Not far to the east, Lago Maicá is a gorgeous floodplain rich in birds and other wildlife, including pink dolphins and sloths.
Just a short bus ride away is Alter do Chão, a cool little town with white-sand river beaches and a laid-back vibe. And this area is steeped in history, from ancient petroglyphs in nearby Monte Alegre to the boom and bust of Amazonian rubber in Fordlândia.