Salisbury Plain is a chalk plateau in central southern England covering 300sqmi. It is part of a system of chalk downlands throughout eastern and southern England formed by the rocks of the Chalk Group and largely lies within the county of Wiltshire, with a little in Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known landmarks. Largely as a result of the establishment of the Defence Training Estate Salisbury Plain the plain is sparsely populated and is the largest remaining area of calcareous grassland in north-west Europe. Additionally the plain has arable land, and a few small areas of beech trees and coniferous woodland. Its highest point is Easton Hill.