Rangiroa

Part of the Tuamotu Archipelago, Rangiroa is one of the world's largest atolls. It is a ring of low land encircling a deep, crystal-clear turquoise lagoon which is so vast that the whole island of Tahiti could fit inside.

The island, about an hour's flight from Tahiti, offers, among other things, world-class scuba diving. The water is so clear that visibility is estimated at least 150ft (46m), and the temperature delightfully hovers around 80°F (27°C) all year round.

The stretch where the lagoon opens to the ocean, known as Tiputa Pass, is particularly rich in marine life and is recognised as one of the world's greatest shark dive locations. Even snorkellers can appreciate close-up views of the various species of sharks and schools of dolphins that gather in the pass.

By French Polynesian standards, Rangiroa doesn't have much in the way of beaches. But the huge lagoon is home to a charming collection of far-flung islands ( motu) which can be reached on various boat trips and make gorgeous spots for picnics and sun bathing.

Accommodation options on the atoll are quite limited but include a lovely low-key resort near the main village, and an adventurer's paradise on a remote lagoon islet, consisting of a handful of primitive beach bungalows hidden under the palms. Travellers are advised to book accommodation far in advance to avoid disappointment as the island doesn't accommodate that many travellers - but then, that is part of the appeal.