3. Tikehau Island, French Polynesia
The atoll’s oval-shaped lagoon is 27 kilometres (17 miles) long and 19 kilometres (12 miles) wide with a lagoon area of about 461 square kilometres (178 square miles). The atoll is made up of two major islands and numerous islets. The northeastern quarter of the atoll is a single, mostly uninhabited island. The whole atoll is surrounded by an almost continuous coral reef. There is a single pass deep and wide enough for navigation in and out of the lagoon: Tuheiava Pass is located on the western shore. The islands and islets are covered with coconut palms. The main village is called Tuherahera.