Silbury Hill in Wiltshire - together with Stonehenge, Avebury and the remains of numerous barrows - forms part of a Neolithic landscape about which very little is known or understood.
Adam Thorpe describes his book as '"a marble cake of different soils. Memoir, data, theory, streaks of poetry, swirls of fiction" - but he is not alone in having been drawn to explore the meaning of the largest prehistoric mound in Europe. Artists and archaeologists as well as various cults and neo-pagan traditions have focussed on the blank canvas that the hill presents as a way of exploring our complicated relationship with the past and the people who lived there.
"An estimated million hours spent on construction rather than herding or cooking or stitching must have had a point, but we don't get it. Is conjecture a species of fiction? To muddy the difference further, Silbury insisted on being called 'she'. I obeyed, not out of New Age winsomeness but from the influence of country dialect, in which neuter pronouns are as alien as robot leaf blowers."
This chalkland memoir told in fragments and snapshots, takes a circular route around the hill, a monument which we can no longer climb, and celebrates the urge to stand and wonder.
Episode 4:The author meets a pair of enthusiastic Wiccan drummers.
Abridged, directed and produced by Jill Waters
A Waters Company production for BBC Radio 4.