As close as you'll get to experiencing a real Amazonian ecosystem on a half-day trip from Manaus, this 9000-acre park has flooded forests, giant water lilies, large trees, fishing opportunities and a smattering of Amazonian wildlife. It's fairly tame compared to the real thing, with raised wooden walkways and even a restaurant, but it's still a worthwhile introduction.
All tour operators in Manaus can organize visits here, often combining them with visits to the Encontro das Águas and other nearby attractions.