Stonehenge is a prehistoric monument located in the county of Wiltshire, England. Stonehenge is composed of earthworks surrounding a circular setting of large standing stones. Stonehenge was built in three phases. The standing stones were erected around 2200 BC and the circular earth bank 3100 BC. Archaeologists are not really sure about the use of Stonehenge, maybe a mortuary area or a place for religious formalities. The site and its surroundings were added to the UNESCO's list of World Heritage Sites in 1986. Stonehenge itself is owned by the Crown and managed by English Heritage while the surrounding land is owned by the National Trust.