Anavilhanas is an archipelago of around four hundred islands strung for more than a hundred kilometres along the Rio Negro, upstream of Manaus. It is a national park and one of the largest river archipelagos in the world, and from the air it looks like a green braid laid on black water.
The Rio Negro's dark, acidic water has an unexpected benefit: far fewer mosquitoes than on the muddy Amazon proper. The base is Novo Airão, about three hours' drive from Manaus across the bridge over the Negro, where the town's floating deck is known for pink river dolphins that come to be fed — a much-debated attraction, now regulated and limited.
The islands change completely with the seasons. At high water, roughly May to July, the forest floods to the canopy and you move through it in canoes, among the treetops. At low water, from about October to December, white sand beaches appear along the channels. Lodges on the river and in Novo Airão run canoe trips, night caiman spotting and walks in the forest.
For many people this is the better introduction to the Amazon than the busier lodges immediately around Manaus: quieter, clearer and closer to what the river looked like before the city.