Fifty years in the making, Silbury Hill is the largest artificial mound in Europe. It's 130 feet high, its base covers 5 acres and it's constructed of 12 million tons of earth and chalk. When originally erected, the hill would've been white from the chalk used in its construction and it's believed that its base was surrounded by a moat. A recent survey suggests that the hill may have also featured a spiral pathway winding towards its summit. Not only would Silbury have been one of the most spectacular sites visible on the face of the Earth 4,500 years ago, but it would also have been part of an emerging Neolithic ritual landscape - unique and unparalleled anywhere else on the planet.

Silbury Hill's construction commenced around 2660BC. It was built in a series of six terraces - one on top of another, gradually decreasing in size. The gaps between each terrace were then filled with chalk and smoothed to provided a regular slope from top to bottom. Archaeology at the site has revealed a level of sophistication to the construction that seems strikingly at odds with our perception of our Neolithic ancestors.

Given the size of Silbury Hill, it's surprising how little it's visible from the surrounding countryside. The fact that it's built on a low-lying plain means that it's visual impact can only be appreciated from particular points. Once you manage to locate an appropriate view however, this hill will take your breath away. It becomes immediately obvious the scale of the undertaking required to have built it. Even today, this would represent quite an achievement - but 4,500 years ago? You can't fail to be impressed. The size of the workforce alone must have been staggering - especially at a time when our ancestors were still dressed in animal skins using tools no more sophisticated than bits of antler and bone.