Where dunes meet lagoons
© Pakawat Thongcharoen/Moment/Getty Images
These sand dunes only exist because the ocean is so close by, but that's not saltwater we're seeing. Brazil's remote Lençóis Maranhenses National Park is famous for its freshwater lagoons, which fill the dips and valleys amid the dunes each rainy season. Whether you witness them from high above or jump right in for a swim, the interlocking crystalline pools form a surrealist masterpiece that's forever in flux. The lagoons, slowly but surely, will evaporate into shallow puddles by autumn, only to be replenished when stormy weather returns next spring and summer.
Deep, deep desert
Dry, dry desert
Dunes of Denmark