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A man stands on top of Stonehenge as the sun rises on June 21, 2006, in Amesbury, England. An estimated 19,000 people celebrated the start of the longest day of the year at the 5,000-year-old stone circle. Reportedly, only four arrests were made at the all-night party.
Construction around the Neolithic and Bronze Age monument has been dated as far back as 3100 BC--with the stones being erected between 2500 and 2000 BC. There are many stories about who built the monument. One of the most popular theories says that it was built by Druids, Celtic priests who supposedly used it for sacrificial ceremonies. How the mammoth stones were moved by a society with Stone Age technology has confounded experts and led many to believe in extraterrestrial assistance.