Ireland is an island to the north-west of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth.To its east is the island of Great Britain, from which it is separated by the Irish Sea.
The island's geography comprises relatively low-lying mountains surrounding a central plain, with several navigable rivers extending inland. The island has lush vegetation, a product of its mild but changeable oceanic climate, which avoids extremes in temperature. Thick woodlands covered the island until medieval times.