Stonehenge is a prehistoric monument located in Wiltshire, England, about 2 miles west of Amesbury. It was built in several stages between 3000 BC and 1600 BC. Archaeologists believe that the massive sandstone blocks that make up Stonehenge were transported from a quarry in the Marlborough Downs around 25 miles away, then dressed and trimmed with stone tools before being erected on the site.