I have just visited one of the two parks that make up the "Cerrado Protected Areas", that is Chapada dos Veadeiros. Cerrado is the Brazilian savannah, although much greener than other savannah areas of the world. In comparison to Amazon Forest it looks poor in terms of biodiversity, but 1/3 of all Brazilian species (flora and fauna) can be found in cerrado areas.
To enter the National Park of Chapadas dos Veadeiros one must hire a guide that leads you to the two possible treks, both with awesome waterfalls and natural pools to beat the heat. It usually takes a whole day to visit each one of the treks. The highest fall is 120 meters. With luck, some of the species of the cerrado can be sighted, in my case I could see the "gralha-do-campo", a black and blue bird.
The NP is only 230 km from Brasília with plenty of hotels around the city of Alto Paraíso de Goiás.