title: Lençóis Maranhenses National Park
text: Lençóis Maranhenses National Park (Parque Nacional dos Lençóis Maranhenses) is a national park in Maranhão state in northeastern Brazil, just east of the Baía de São José. Protected on June 2, 1981, the  park includes  of coastline, and an interior composed of rolling sand dunes. During the rainy season, the valleys among the dunes fill with freshwater lagoons, prevented from draining due to the impermeable rock beneath. The park is home to a range of species, including four listed as endangered, and has become a popular destination for ecotourists.
  
  Physical geography 
  The park is located on the northeastern coast of Brazil in the state of Maranhão along the eastern coast, bordered by  of beaches along the Atlantic Ocean. Inland, it is bordered by the Parnaíba River, the São José Basin, and the rivers of Itapecuru, Munim, and Periá. The park encompasses an area of , composed mainly of expansive coastal dune fields (composed of barchanoid dunes), which formed during the late Quaternary period.
  
  While much of the park has the appearance of a desert, the area receives about  of rain per year, while deserts, by definition, receive less than  annually. About 70% of this rainfall occurs between the months of January and May.
  
  The sand is carried to the park from the interior of the continent by the Parnaíba and Preguiças rivers, where it is then driven back inland up to  by winds, creating a series of sand dunes rising as much as  tall. During the rainy season, between the months of January and June, the rainstorms fill the spaces among the dunes with fresh water lagoons of up to  in length and  in depth, and together comprising as much as 41% of the area of the park. The water in the lagoons is prevented from draining by a layer of impermeable rock located beneath the sandy surface. The lagoons typically have a temperature between  and , pH of between 4.9 and 6.2, and low levels of dissolved nutrients. When the dry season returns, the pools quickly evaporate, losing as much as  of depth per month.
  
  In the interior of the park are located two oases or restingas, Queimada do Britos, covering an area of , and Baixa Grande, covering an area of .
  
  The area of the park has an average annual temperature of between  and  and an annual temperature variation of about 1.1 °C (2 °F).
  
  Ecology
  The lagoons in the park are often interconnected with one another, as well as with the rivers that run through the area. They are home to a number of fish and insect species, including the wolf fish, which burrows down into wet layers of mud and remains dormant during the dry season. Besides the dunes that form the centerpiece of the park, the ecosystem also includes area of restinga and mangrove ecosystems.
  
  The park is home to four species listed on the Brazilian List of Endangered Species, the scarlet ibis (Eudocimus ruber), the neotropical otter (Lontra longicaudis), the oncilla (Leopardus tigrinus) and the West Indian manatee (Trichechus manatus). The park also includes 133 species of plants, 112 species of birds, and at least 42 species of reptiles.
  
  Tourism 
  
  Lençóis Maranhenses National Park receives as many as 60,000 visitors a year. Common activities within the park include surfing, canoeing and horseback riding.
  
  In popular culture
  
  The park was featured in the Brazilian film The House of Sand. Kadhal Anukkal, a song from an Indian Tamil language film Enthiran starring Rajnikanth and Aishwarya Rai Bachchan was also shot here. The films Avengers: Infinity War (2018) and Avengers: Endgame (2019) used the park's landscape as the planet of Vormir. A concert performed by the music group RY X was filmed by the YouTube channel Cercle in 2022
  
  See also
  
  Genipabu
  Conservation in Brazil
  List of national parks of Brazil
  
  Notes
  
  References
  
  External links
  
   Lençóis Maranhenses National Park's Official site
  
  National parks of Brazil
  Protected areas of Maranhão
  Protected areas established in 1981