Silbury Hill acquired its distinctive shape in more modern times, according to new archaeological evidence. It is traditionally thought that the hill, with its steep banks and flat top, was conceived and completed in pre-historic times.
But new research presented in a new book suggests the final shape was a late Anglo-Saxon innovation. The hill, near Avebury in Wiltshire, is Europe's largest man-made prehistoric mound.
Click here to read this article and video from BBC News