When you first see Silbury Hill in Wiltshire in just looks so extraordinary – is it natural, is it man-made, what was it for, who made it and why? You can’t help but ponder on these questions, and actually you won’t ever know most of the answers except yes, it is man-made. It is the largest man-made mound anywhere in Europe, and it is similar in height and volume, and built roughly at the same time as some of the Egyptian pyramids. It is estimated that it was finished in about 2400 BC, and although you might assume it is to mark a burial, in fact there is no evidence that it was – nothing has been found. It must have been an important and significant structure, with great meaning and importance – because just imagine how long it would have taken to make using only bone tools; how ‘rich’ and secure the people must have been to have such a large workforce devoted to that and not to farming or fighting. Its purpose and it significance will probably remain forever unknown.