"The Lençóis Maranhenses National Park is located in Maranhão state, in northeastern Brazil. And it’s just stunning with lagoons spread out the ‘desert’ of white sand dunes.
Lying just outside the Amazon basin, the region is subject to a regular rain season during the beginning of the year. The rains cause a peculiar phenomenon: fresh water collects in the valleys between sand dunes, spotting the desert with blue and green lagoons." -Where the Cool Things Happen