National Geographic : 2010 Jul
• S , the dunes look like white linens hung out to dry on a windy afternoon. In fact, the name of this place, Lençóis Maranhenses, means the "bedsheets of Maranhão," the state in Brazil on the tropical northeastern coast where the half- moon-shaped dunes are found. By any name it is a magical desert, with wave a er wave of shim- mering white sand. Shoals of silvery sh swim in brilliant blue and green pools le behind by the rains. Shepherds lead caravans of goats over towering dunes. And shermen head out to sea, guided only by the stars and the ghosts of old shipwrecks. "It feels like a parallel world," says Carolina Alvite, former director of the 600-square-mile national park created three decades ago to pro- tect this unlikely ecosystem. It's as if the sea near the Bahamas suddenly appeared like a mirage in the middle of the Sahara. Only in this desert the mirage is real. Actually, by the most technical of standards, the Lençóis isn't really a desert, says Antonio Cordeiro Feitosa, a geographer at the Federal University of Maranhão. Forty-seven inches or so of rain fall on the region a year. By de nition, a desert averages fewer than ten inches a year. And it is the presence of water that makes the sandscape possible. Two nearby rivers, the Parnaíba and Preguiças, carry sand from the interior of the continent to the Atlantic, where ocean currents push them westward. Much of the sediment is deposited along the park's 44-mile-long shoreline. Here, during the dry season, especially in October and November, a relentless northeasterly wind drives the sand Raised by residents of the park, goats graze freely on wild vegetation during the lush months of rain, then are rounded up when the dry season arrives. George Steinmetz photographed Libya's Sahara for the October 2009 issue. Ronaldo Ribeiro is the senior editor of the Geographic's Brazilian edition.