Stonehenge's altar stone was quarried over 4,600 years ago, far from the Salisbury Plain in Wiltshire. But experts now know where it originated.

Looking at the extent of stone circles in Wales, the growth of Celtic hill forts and what they reveal about the changing society of that time.

Evidence of two previously unknown prehistoric stone circles has been uncovered in southern England—with one site seemingly displaying similarities to the early phase of the iconic Stonehenge.