With the invention of agriculture, humans began to settle in permanent farming communities, which profoundly changed their way of life.
They began to place some of their dead in large communal tombs - long barrows.
These are large earth mounds up to 70m long, with 2 long ditches on either side, typically built on hills.
They have an entrance, a long corridor and a few rooms branching out on either side.
It's difficult to spot them, and they're often dismissed as mere "earth mounds" - but building structures such as these would have required a tremendous amount of work.
First humans would have had to deforest the land (using polished stone axes), then dig the earth (using deer antlers), then cut multiple-ton rocks in quarries and transport them tens of kilometres to the site.
Long barrows are the oldest
Around 40,000 Neolithic long barrows survive to this day!
West Kennet and Normanton Downs are great examples.
West Kennet is one of the largest in the UK.
It had 50 people buried here over 1,000 years and was mysteriously sealed up around 2000 BC and a fake entrance created!
Normanton Down is the largest group of barrows in the UK.
It has one Neolithic long barrow and 40 Bronze Age round barrows.
As experts at Maeshowe, a famous long barrow on the island of Orkney, describe it, long barrows were the "triumphs of the human spirit in early ages and isolated places… an expression of genius within a group of people whose other tombs were claustrophobic chambers in smaller mounds".