Palmas is the capital of the Brazilian State of Tocantins. Like the country's capital, Brasilia, and several other state capitals, it was built out of nowhere (in 1990) to house the government of its new-born state.
This is pretty much the middle of nowhere. Both bus and plane connect better southwards, via Brasilia.
The city is interesting as a study of urbanism. It was dimensioned for several times its current population.
There is a fresh water beach a couple of km from the center. Take any bus that goes to the university.