Some islands cover a smaller area than a city block. A small island is called an islet. The distinction between a continent and an island is based on size. Australia is more than three times as large as Greenland. Because of its size, geographers class it as a continent.
Islands make up the entire land area of some countries, including Japan and the Philippines.
Millions of people live on such islands. Other islands have no people. Some of these islands, such as Pelican Island in Florida and the Oregon Islands in Oregon, are wildlife refuges. Throughout history, islands have served as stopping points on migration and trade routes and as stations for refueling and supplying ships. Islands have thus aided the spread of people, animals, and plants from one continent to another.