Explored in a recent Channel 5 television documentary titled 'Stonehenge: The New Revelations', a new study proves the roughly 2 kilometre diameter ring of pits discovered last year surrounding the Neolithic site of Durrington Walls were human-made. Dug into the landscape almost 4,500 years ago at the end of the Neolithic period, the "Great Durrington Ring" may be the world's largest Neolithic monument, and the very last in Britain. Durrington Walls sits precisely at its centre, about 2.5 kilometres northeast of Stonehenge.
     All the pits are similar, about 10 metres across and 5 metres deep. Archaeologist and study leader Professor Vince Gaffney and his team examined 9 of some 20 surviving pits, declaring them the largest prehistoric structure found in Britain. Tests date the pits to around 2400 BCE, and show they were used from the late Neolithic until the middle Bronze Age, long after the monumental building phases of Stonehenge. Then they were left to fill naturally.  
     Extracting soil samples from deep within the pits, Gaffney's team was able to date the chalk, soil, bones, and other animal remains to the period coinciding with the construction of the enclosed Durrington Walls 'superhenge'. Previous studies at Durrington Walls have revealed ancient house structures, suggesting the people who first lived there would have been involved with the erection of Stonehenge's sarsen stones 500 years after that monument's initial formation.

Edited from The Guardian (23 November 2021), Express (11 December 2021), Sci News (22 June 2020)