Thousands of small islands scattered in the western Pacific Ocean make up this subregion of Oceania which has a similar cultural history to Melanesia and Polynesia. These islands are part of five main archipelagos and politically shared by six sovereign nations. The five main island groups that make up this region are the Caroline Islands, the Gilbert Islands, Line Islands, Mariana Islands and the Marshall Islands which are shared by the United States, Republic of Kiribati, Palau and the Federated States of Micronesia. Nauru is the only sovereign, separate island nation.
Most of the islands in Micronesia are coral atolls, which began as coral reefs and extended up the slopes of volcanoes which emerged from the sea. These corals have continued to grow and form landmasses even after the volcano has been resubmerged. Predictably, the landscape is quite stunning as is the surrounding azure waters of the ocean.