Aerial image of Silbury Hill, a prehistoric human-made chalk and clay mound near Avebury, UNESCO World Heritage Site, Wiltshire, England, United Kingdom, Europe

Aerial image of West Kennet Long Barrow, a Neolithic tomb or barrow, on a prominent chalk ridge, near Silbury Hill, Avebury, Wiltshire, England, United Kingdom, Europe

Silbury Hill mound, the largest prehistoric manmade structure in Europe, Wiltshire, England, United Kingdom, Europe

No Entry sign at neolithic prehistoric mound of Silbury Hill, to avoid further human erosion, Wiltshire, England, Silbury Hill mound, the largest prehistoric manmade structure in Europe, Wiltshire, England, United Kingdom, Europe

Silbury Hill mound, the largest prehistoric manmade structure in Europe, Wiltshire, England, United Kingdom, Europe

Silbury Hill, the largest man made mound in Europe dating from the Neolithic period, near Avebury, Wiltshire, England, United Kingdom, Europe

Silbury Hill neolithic site, the largest manmade prehistoric structure in Europe, Wiltshire, England, United Kingdom, Europe

Silbury Hill, a Stone Age burial mound, Wiltshire, England, UK, Europe

Silbury Hill neolithic site, the largest prehistoric manmade structure in Europe, Wiltshire, England, United Kingdom, Europe

Baled hay in field below Silbury Hill, Wiltshire, England, United Kingdom, Europe

Largest man made mound in Europe, purpose unknown, Silbury Hill, Wiltshire, England, United Kingdom, Europe

Silbury Hill, Wiltshire, England, United Kingdom, Europe