One of Brazil’s most spectacular natural attractions, the Lençóis Maranhenses—250 kilometers (155 miles) east of São Luís—is a fantastic desert of immense white sand dunes that bear a striking resemblance to billowing lençóis, or sheets. Some of the dunes are 50 meters (164 feet) high. Every year when the rains come (from December to May), their valleys fill with water, forming a series of jade lagoons whose mirror-like surfaces reflect the piercing blue sky filled with drifting clouds and gliding egrets.

The majesty of the landscape is impossible to express. But the sense of timelessness is impressive; particularly when trekking through the sand, you turn around to see that the wind has wiped out the only sign of civilization—the footprints you made only five minutes earlier.

The Lençóis Maranhenses are within the Parque Nacional dos Lençóis Maranhenses, a protected area that is around the size of Rhode Island. No cars are allowed in the park (although Jeeps can take you within close proximity). To explore the dunes on foot, you’ll need to hire a guide or go as part of an excursion. The closest town is nearby Barreirinhas, a six-hour bus ride from São Luís, where there are plenty of hotels and restaurants as well as guides and tour operators.

The best time to visit are the sunny days between June and September when the lagoons are still full enough to bathe in (by December, they’ve often completely evaporated). You can explore the park from Barreirinhas by Jeep or boat.

Getting to Parque Nacional dos Lençóis Maranhenses

There are various ways of getting to Barreirinhas from São Luís. Cisne Branco (tel. 98/3243-2847) operates several daily buses that depart from the rodoviária. The trip takes around five hours. Should you want more comfort (i.e., air-conditioning), contact VanExpress (tel. 098/3256-4027), a minivan service that picks you up at your São Luís hotel. Fewer stops speed up the journey significantly to 3–4 hours. Departures, however, depend upon demand.

The fastest and most scenic, but also most expensive, mode of transportation is flying. Litorânea Aero Taxi (tel. 98/3217-6181, www.litoraneataxiaereo.com.br) offers several daily flights that take 40 minutes and cost R$230. A definite bonus is the overhead view of the dunes.

Although it’s not that practical—a car is useless in the dunes—should you want to drive, the BR-135 and MA-402 highways that lead to Barreirinhas are in relatively good condition.

From São Luís, various tour agencies can organize your trip to the Lençóis Maranhenses—whether it’s simply reserving transportation or customizing an entire package that includes Jeep and boat outings. Giltur (Rua do Giz 46, Praia Grande, tel. 98/3232-6041, www.giltur.com.br) is recommended, as is Ecodunas (tel. 98/3349-0545, www.ecodunas.com.br), which organizes a variety of adventure excursions that depart from São Luís.