Avebury is a Neolithic henge monument containing three stone circles, around the village of Avebury in Wiltshire, Southwest England. Unique amongst megalithic monuments, Avebury contains the largest stone circle in Europe and is one of the best-known prehistoric sites in Britain. It is both a tourist attraction and a place of religious importance to contemporary Pagans. Constructed around 2600 BC, during the Neolithic or 'New Stone Age', the monument comprises a large henge that is a bank and a ditch. Inside this henge is a large outer stone circle with two separate smaller stone circles situated inside the center of the monument. Its original purpose is unknown, although archaeologists believe that it was most likely used for some form of ritual or ceremony. The Avebury monument was a part of a larger prehistoric landscape containing several older monuments nearby. Evidence of a common denominator between ancient sites came when English Heritage had to undertake a conservation project to save Silbury Hill from collapse. During this work, archaeologists discovered that the Neolithic builders had introduced hundreds of sarsen stones into the hill, which they believe were considered sacred by humans of the period. The interesting fact is that sarsen stones were also incorporated into Stonehenge, brought down from the Marlborough Downs, near Avebury. For further reference, archaeologist Jim Leary noted that the discovery of sarsen stones inside the final phase of the Silbury Hill monument had been a surprise. Leary argued that Silbury, and monuments such as Stonehenge and the stones at Avebury, had been built in response to a period of great change in Britain, which at the time was being influenced by an influx of European cultures.