Bluehenge

Bluestonehenge or Bluehenge (also known as West Amesbury Henge) is a prehistoric henge and stone circle monument.
It was discovered by the Stonehenge Riverside Project about south-east of Stonehenge in Wiltshire, England. All that remains of the site is the ditch of the henge and a series of stone settings, none of which is visible above ground.
Excavation revealed two flint chisel arrowheads in a style commonly used during 3400-2500 BC. The stones have been put up in that period. It is estimated that there may have been as many as 27 stones in a circle 33 feet (10 m) wide.
The site was excavated in August 2008 and again in August 2009. It is considered an important find by archaeologists.
The name "Bluestonehenge" is from the small stone chips found in some of the stone settings. These bluestones are also found in Stonehenge and consist of a wide range of rock types originally from Pembrokeshire West Wales, some away. Archaeologists think any bluestones in the circle may have been removed around 2500 BC and used at Stonehenge, which had major rebuilding at about that time.
The stone circle settings were surrounded by a henge, comprising an ditch and outer bank which appears to date from approximately 2400 BC.