Stonehenge is one of the most prominent prehistoric monuments in Britain. The Stonehenge that can be seen today is the final stage that was completed about 3,500 years ago.
According to the monument's website, Stonehenge was built in four stages:
First stage: The first version of Stonehenge was a large earthwork or Henge, comprising a ditch, bank and the Aubrey holes, all probably built around 3100 BC.
The Aubrey holes are round pits in the chalk, about one metre (3.3 feet) wide and deep, with steep sides and flat bottoms.
Stonehenge (pictured) is one of the most prominent prehistoric monuments in Britain
They form a circle about 86.6 metres (284 feet) in diameter.
Excavations revealed cremated human bones in some of the chalk filling, but the holes themselves were likely not made to be used as graves, but as part of a religious ceremony.
After this first stage, Stonehenge was abandoned and left untouched for more than 1,000 years.
Second stage: The second and most dramatic stage of Stonehenge started around 2150 years BC, when about 82 bluestones from the Preseli mountains in south-west Wales were transported to the site. It's thought that the stones, some of which weigh four tonnes each, were dragged on rollers and sledges to the waters at Milford Haven, where they were loaded onto rafts.
They were carried on water along the south coast of Wales and up the rivers
