Stonehenge is a prehistoric monument on the Salisbury Plain in Wiltshire, England, two miles (3 km) west of Amesbury. It consists of an

outer ring of vertical Saracen standing stones, each about 13 feet (4.0 m) high, seven feet (2.1 m) wide, and weighing about 25 tons,

which is topped by connecting horizontal lintel stones. . Inside is a ring of small blue stones. Inside are free-standing trilithons,

two bulkier vertical sarances connected by a lintel. The entire monument, now in ruins, is aligned towards sunrise on the summer solstice.

Stones including several hundred tumuli (burial mounds) have been set within the quakes, among the densest complex of Neolithic and

Bronze Age monuments in England.Archaeologists believe that Stonehenge was constructed from 3000 BC to 2000 BC. The surrounding circular

earthen ledges and moats, which constitute the earliest phase of the monument, date to about 3100 BC. Radiocarbon dating suggests

that the first bluestones were raised between 2400 and 2200 BC, although they may be at the site as early as 3000 BC.