Rainwater Between Dunes

Rainwater Between Dunes is an original illustration set in Lençóis Maranhenses, Maranhão, Brazil. It lies in equatorial latitudes, where the climate is tropical savanna — a pronounced dry season.

From a high oblique viewpoint, sweeping white dune ridges repeat toward the horizon while clear turquoise and cobalt pools fill the curved hollows between them. Sparse dark-green vegetation gathers only at the margins, and tiny human figures provide scale without turning the immense sand-and-water pattern into a recognizable landmark scene.

Why do blue lagoons appear between white dunes after the rains?

Because seasonal tropical rain falls onto a vast dune field underlain by relatively impermeable material, water collects in low interdune basins faster than it can drain away. The pools expand during the wet season and shrink during the dry months, while wind continually reshapes the pale sand ridges around them. That unusual pairing of mobile white dunes and temporary freshwater lagoons creates the geographic signature of coastal Maranhão.

Terpano is a free daily geography puzzle. You study one original illustration, place a pin on a borderless terrain map, and see how close you were. There is no account and no sign-up; progress stays in your own browser. It plays in 11 languages.