Everyone loves a mystery – and few things are more massively mysterious than Silbury Hill. This vast artificial mound is the largest in Europe. It is surrounded by an oddly shaped moat that fills with water in wet weather. It has stood here for thousands of years, but who built it and why nobody is entirely certain.
It forms part of the sprawling prehistoric ritual complex of standing stones, henges and tombs that surrounds the Wiltshire village of Avebury.
Find out more: https://en.wikipedia.org/wiki/Silbury_Hill