Stonehenge As the most famous prehistoric monument in Britain,Stonehenge is a group of huge monuments of giant rock slabs on Salisbury Plain in Southwest England built by the Stone Age peoples.It is generally believed that Stonehenge served some sort of religious purposes. fppt.comStonehenge • As the most famous prehistoric monument in Britain, Stonehenge is a group of huge monuments of giant rock slabs on Salisbury Plain in Southwest England built by the Stone Age peoples. It is generally believed that Stonehenge served some sort of religious purposes