Tocantins is the newest Brazilian state, formed in 1988 from the northern part of Goiás. Located in the center of Brazil and belonging to the huge part which is called Norte, it is located in the tropics, only a little south of the equator. Its landscape is both, Amazon rainforest and coastal savanna. The two main rivers, the eponymous Rio Tocantins and Rio Araguaia, are used to produce hydroelectric power, which is the main resource of the state. The area was inhabited only by native people until the construction of the road BR-010.
The state of Tocantins is located in the middle of the Central Brazil Shield, the rocks are Archean crystalline, metamorphic and plutonic rocks covered by some sedimentary rocks. Typical are vast sandstone plateaus with an altitude between 300 m a.s.l. and 600 m a.s.l. and rivers which have cut deep valleys into those plateaus. There are only some spots of limestone, which means only a small amount of caves. There are also no mineral deposits, so we have neither show caves nor show mines in the area. Because of the lack of human civilization there are also no artificial underground structures. The only site we could list was a karst spring of great beauty.