Atoll Lagoon

Atoll Lagoon is an original illustration set in Maldives Atolls. It lies in equatorial latitudes, where the climate is tropical rainforest — hot and wet all year.

A curving coral reef ring separates glassy turquoise lagoon water from deep indigo ocean. A white sandbar carries a single line of coconut palms. Waves break in a thin white seam along the outer edge, and the equatorial noon sun leaves almost no shadow.

Why does an atoll form a ring with a lagoon in the middle?

An atoll is a fringing reef that outlived the island it grew around: the volcano subsided, the coral kept building upward toward the light, and a ring was left with a lagoon where the peak used to be. That only works in water warm enough for reef coral year-round. The sharp colour break marks where the reef drops away into deep ocean.

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.