An enormous field of white sand dunes — 155,000 hectares of them — crossed by thousands of crystal-clear blue and green lagoons that appear each rainy season, fed by rainfall trapped between dunes in a landscape that is simultaneously desert and lake district.
By every definition, Lençóis Maranhenses should be a desert. It receives almost no vegetation, the sand is white and fine, and the dunes reach 40 meters high. But it is not a desert. It receives 1,600 millimeters of rain per year.
The rain falls between January and June, collecting in the valleys between the dunes — which sit above an impermeable rock layer that prevents the water from draining. The lagoons that form are not connected to rivers or groundwater. They exist entirely because the dunes hold them in place. Their color is extraordinary: the finest white silica sand beneath perfect rainwater creates turquoise and deep blue hues that shift depending on depth and the angle of the sun.
By September, most lagoons have evaporated. By December, the landscape is entirely dry again — a vast white field of dunes stretching to every horizon, blown by coastal winds into slow-moving shapes that reset the landscape each year. Then January comes, and the water returns.
The fish that populate the lagoons during wet season migrate in from the rivers during the flooding. When the lagoons evaporate, their eggs remain dormant in the sand, waiting for the next rainy season. This cycle has repeated for as long as the formation has existed.
The name means "bedsheets" in Portuguese — a reference to the white expanse of dunes seen from above. Seen from the air or from a high dune during wet season, with thousands of lagoons glittering between white sand ridges, the description is almost too modest.