Mark Bowden, Sharon Soutar, David Field

Stonehenge is a prehistoric megalithic structure on Salisbury Plain in Wiltshire, England, two miles (3 km) west of Amesbury. It consists of an outer ring of vertical sarsen standing stones, each around 13 feet (4.0 m) high, seven feet (2.1 m) wide, and weighing around 25 tons, topped by connecting horizontal lintel stones which are held in place with mortise and tenon joints—a feature unique among contemporary monuments. Inside is a ring of smaller bluestones. Inside, these are free-standing t…