Evidence of large-scale prehistoric feasting rituals found at Stonehenge could be the earliest mass celebrations in Britain, say archaeologists.
The study examined 131 pigs' bones at four Late Neolithic sites, Durrington Walls, Marden, Mount Pleasant and West Kennet Palisade Enclosures.
The sites, which served Stonehenge and Avebury, hosted the feasts.
Researchers think guests had to bring meat raised locally to them, resulting in pigs arriving from distant places.
The results of isotope analysis show the pig bones excavated from these sites were from animals raised in Scotland, the North East of England and West Wales, as well as numerous other locations across Britain.
Study lead Dr Richard Madgwick from the University of Cardiff said: "These gatherings could be seen as the first united cultural events of our island, with people from all corners of Britain descending on the areas around Stonehenge to feast on food that had been specially reared and transported from their homes."
Dr Madgwick said finding pigs in the vicinity of the feasting sites would have been "relatively easy" making the fact they brought the animals long distances "arguably the most startling finding" as this would have required "a monumental effort".
"This suggests that prescribed contributions were required and that rules dictated that offered pigs must be raised by the feasting participants, accompanying them on their journey, rather than being acquired locally," he said.