Mystery surrounds these wooden circles found near Stonehenge after it was revealed they are 800 years older than scientists had thought.
Radiocarbon dating showed the structures in Avebury, Wiltshire, may have actually been around since 3300 BC.
That would make them older than Stonhenge (2500BC), which is located 20 miles away.
Expert Alex Bayliss, from Historic England, told the Times: ‘The date of 3300BC puts the palisades in a completely different context; it’s the end of the early neolithic, when there’s a blank in our knowledge of the big monuments of the time’
Researchers believe the site, which is 2.5 miles (4km) long and consists of around 4,000 trees, was used for rituals.
Experts had previously determined rings of fire were created by burning down timber palisades but were not sure exactly why this was done.
Dr Bayliss added: ‘One of the hypotheses is that one could have been for women and the other for men to use for rituals.
‘We have an entirely new kind of monument that is like nothing else ever found in Britain’.
The wooden circles, which were discovered in the 1980s, are even more impressive than the ones at Woodhenge, which is closer to Stonehenge.
Just one of the structures measured 250 metres in diameter, which is far greater than Woodhenge.