No one knows the true depth of this crystal-clear cenote (natural pool); researchers have only reached a depth of 200m and that's not even the cave lake's deepest part. You can snorkel and marvel at the seemingly infinite blue, interspersed with drowned tree trunks, but it's scuba divers and cave divers (appropriate certification mandatory) who get the best of this watery world.

Lagoa Misteriosa can get rather crowded. From mid-October to mid-April, algae make the visibility poor so it only opens for deeper (25m) diving excursions.