Ilha do Bananal

The Araguaia divides around Bananal and does not rejoin for some three hundred and fifty kilometres, leaving an island of about twenty thousand square kilometres entirely surrounded by river - which is what makes it the largest fluvial island in the world, a distinction worth stating carefully, since Marajo at the Amazon's mouth is bigger but is bounded partly by the Atlantic rather than by river alone. Bananal is seasonally flooded cerrado and gallery forest, and its status is layered: the northern third is Araguaia National Park, and almost all of the rest is the Ilha do Bananal indigenous territory of the Javaé and Karajá, so access is governed by permits and by community authorisation rather than being open. Giant otters, jaguar, macaws and pirarucu are here.

What you actually see

• The largest river island on earth - twenty thousand square kilometres inside a split river.
• A river that parts for 350 km - the Araguaia and the Javaés arms rejoining downstream.
• Javaé and Karajá territory - indigenous land covering most of the island.
• Seasonally flooded cerrado - the wetland the Araguaia leaves behind each year.

When to go

June to October, when the water drops and beaches appear. Three days.

Honest expectations

Most of the island is indigenous territory and cannot be entered without community authorisation; the national park needs an ICMBio permit. There is no tourist infrastructure. Access is by boat and slow.

Nearby

Cantao State Park is north on the same river; Palmas is east.