A temporary waterpark

Lençóis Maranhenses National Park receives close to 50 inches of rain annually, and about 70% of that falls during the rainy season between January and May. The rainwater fills the troughs between the dunes, and an impermeable layer of rock beneath the sand prevents drainage, causing numerous lagoons to form. Temporary as they are, the ribbonlike lakes beckon swimmers and other watersports enthusiasts—like these kiteboarders—to enjoy them before they evaporate. Which they do quickly: Once the dry season hits, the pools lose up to 3 feet of depth per month until the next rain cycle replenishes them.