Rangiroa, Polynesia

Rangiroa, which means "vast sky" in Tuamotuan, is the largest atoll in the Tuamotus and one of the largest in the world. The atoll consists of about 415 motus, islets and sandbars comprising a total land area of around 170 square kilometers. Two passes or channels, named Tiputa and Avatoru, allow the Pacific waters into and out of the lagoon twice daily when the tides turn. As a diver, you can watch dolphins play, leap and jump in synchronized patterns on the surface and swim with hundreds of sharks below. Occasionally, you might even see turtles, manta rays, leopard rays and whales.

Location: A 10-minute boat ride from shore

Depth: 45 meters

Visibility: 50 meters