The Lencois Marahnenses National Park, in Maranhao State (north-east) is definitely one of the most beautiful places. It's an ecosystem formed by white sand dunes of about 383.000 acres and its name comes from the fact it looks like bedsheets (lencois in Portuguese). These are lagoons which fill up with rainwater, especially until June: so they're a unique landscape worldwide to see. Here you can find mangroves, deserted beaches, buritis (a kind of palm tree) and the Preguicas River contributes to shaping the park's biodiversity. This territory has been formed over thousands of years, while the sand is deposited at the mouth of rivers and brought back to the continent by winds and sea currents: the dunes advance 31 miles into the continent and stretch along 27 miles of coastline. Some of the lagoons are huge, beyond the fact they're truly stunning. You can reach the park leaving the state capital, Sao Luis, for 156 miles.