Gnaviyani Atoll.

Gnaviyani Atoll is the most unusual atoll in the Maldives — a single-island atoll consisting of Fuvahmulah Island, a circular landmass with freshwater lakes, fertile soil, and distinct flora found nowhere else in the country. It's the only reliable tiger shark dive destination in the Maldives, with year-round encounters at the Fuvahmulah harbour cleaning station. The atoll also offers thresher shark, oceanic manta and pelagic diving, drawing specialist divers from around the world.