The name of this 1550-sq-km national park refers to its immense expanse of dunes, which look like lençóis (bed sheets) strewn across the landscape and stretch 70km along the coast and up to 50km inland. Situated halfway between São Luís and the Piauí border, the park also includes beaches, mangroves, lagoons and some interesting fauna, especially turtles and migratory birds. It is a spectacular place, especially from March to September, when rain that has filtered through the sand forms crystal-clear pools and lakes between the dunes.
