Stonehenge was built as part of a fertility cult with the stones positioned to cast phallic shadows inside the monument during Midsummer, a new study suggests.
Professor Terence Meaden, an archaeologist, examined nearly 20 stone circles throughout Britain, filming their changing silhouettes during sunrise on ritually significant dates of the year.
Experts already knew that the 6000-year-old Neolithic monuments were aligned on the solstices, but it is the first time it has been suggested that the orientation of the stones was specifically designed to create a "moving spectacle".
Meaden said the builders of Stonehenge, in Wiltshire, and other megalithic circles, had created a "play without words" in which one special stone cast a growing phallic shadow which penetrated the egg-shaped monument before hitting a central "female" stone symbolising fertility and abundance.
The circular shape of the monuments allowed the same "play" to recur at important dates in the Neolithic farming calendar, he believes.