
Located on Brazil’s northeastern coast, Lençóis Maranhenses National Park is home to the country’s largest coastal dune field. More than 60,000 travellers visit the 1,550sqkm park each year to explore this unlikely ecosystem, where crescent-shaped sand dunes, formed by wind and ocean currents, can reach up to 40m high. Due to the heavy rainfall in the area, fresh water lagoons then form in between them.
All pictures: http://www.bbc.com/travel/slideshow/20130408-brazils-shifting-sandscapes
Now that seems like an interesting place to visit.