Stonehenge is a prehistoric monument in Wiltshire, England, built about 5,000 years ago. Its first unique stone circle was erected in 2500 BC. About 200 or 300 years later the central bluestones were rearranged to form a circle and inner oval. The last prehistoric activities at Stonehenge were the digging around the stone settings of two rings of concentric pits, the so-called Y and Z holes, radiocarbon dated by antlers within them to between 1800 and 1500 BC. Later in the early Bronze Age, many burial mounds were built near by. Today, it forms the heart of a World Heritage Site of prehistoric monuments.
Stonehenge
