Stonehenge is probably the most famous henge in the world. A prehistoric World Heritage Site two miles north of Salisbury in Wiltshire, England, it was built over 4000 years ago and remains one of Britain's greatest mysteries.
There were three main building phases between about 3100 BC and 1950 BC. The first circle, ~3000 BC, was made of timber. The post holes for the timber have been found. Around 2600 BC, the builders gave up timber in favour of stone. Most of the construction took place between 2640 and 2480 BC.
The first stone circle was a set of 'bluestones', made of dolerite. The holes held up to 80 standing stones, only 43 of which can be traced today. What is interesting about this is that the stones are absolutely massive and in those times there would have been no way to transport such rocks. People used to think that the stones had been brought from the Preseli Hills, 160 miles away in Pembrokeshire, Wales. Another theory is that they were brought much nearer to the site as glacial erratics by the Irish Sea Glacier. Recently a group of people from Wales tried to re-enact one of the theories of how the stones were moved. They attempted to move a bluestone from Wales to Wiltshire, but the attemot failed when they tried to transport the stone by sea and it ended up at the bottome of the Bristol Channel.
Later, ~2400 BC, 30 huge grey sarsen stones were brought to the site. They were erected in a circle 33 metres in diameter, with lintels on top of the standing stones. The remaining blue circles were placed as an inner circle. The site remained in use until the Bronze Age. The Stonehenge that exists today is made of all the original stones, however some of the stones have been moved into an upright position.
There are also several passage tombs and many tumuli nearby.
No one knows who built Stonehenge or why they built it. During the summer solstice, the sunrise lines up with some of the stones in a particular way, which has led a popular theory to be that the stones may have been a calendar in ancient times. In Egypt and South America similar ancient buildings that show the time of the solstice have been discovered. Stonehenge is also known as the 'Giant's Dance' and the some people believed the stones were erected by Devil, while in the C18th people believed scrapings from stones could heal wounds.