Micronesia (UK: /ˌmaɪkrəˈniːziə/, US: /-ˈniːʒə/) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and Melanesia to the south—as well as with the wider community of Austronesian peoples. The region has a tropical marine climate and is part of the Oceanian realm. It includes four main archipelagos—the Caroline Islands, the Gilbert Islands, the Mariana Islands, and the Marshall Islands—as well as numerous islands that are not part of any archipelago. Human settlement of Micronesia began several millennia ago. The Micronesian people are considered, by linguistic, archaeological, and human genetic evidence, a subset of the sea-migrating Austronesian people, who include the Polynesian people and the Melanesian people. Based on the current scientific consensus, the Austronesian peoples originated from a prehistoric seaborne migration, known as the Austronesian expansion, from pre-Han Taiwan, at around 3000 to 1500 BCE. Austronesians reached the northernmost Philippines, specifically the Batanes Islands, by around 2200 BCE. Austronesians were the first people to invent oceangoing sailing technologies (notably catamarans, outrigger boats, lashed-lug boat building, and the crab claw sail), which enabled their rapid dispersal into the islands of the Indo-Pacific. From 2000 BCE they assimilated (or were assimilated by) the earlier populations on the islands in their migration pathway. (Source: Wikipedia.org, CC BY-SA)