It has long been speculated the huge man-made structure in Avebury was an ornate grave or a ceremonial hilltop for religious rituals . But expert claims mound was built as lighthouse and harbour to help Neolithic traders navigate post-glacial waterways . Believes southern Britain was a series of islands linked by waterways , channels and swollen rivers , and that Stonehenge was located on coast .
It has long been speculated the huge man-made structure in Wiltshire was an ornate grave or a ceremonial hilltop for religious rituals . But expert claims mound was built as lighthouse and harbour to help Neolithic traders navigate post-glacial waterways . Believes southern Britain was a series of islands linked by waterways , channels and swollen rivers , and that Stonehenge was located on coast .