Stonehenge is not the only massive (and puzzling) stone circle in the world. It's not even the only circle in the area, anymore! Archaeologists have discovered a site on Stonehenge land they believe to have been a large wooden circle, contemporary to Stonehenge.
Check it out: "Stonehenge twin discovered stone's throw away".
It is generally believed that giant circles, be they stone or wood, were built to help civilizations follow astronomical and celestial events. The mystery that surrounds them is unavoidable.
In fact, two children's books I recently re-read build on stone circles' mystical, inspiring qualities: In the Stone Circle (Kimmel) and The China Garden (Berry). Laden with mystery, love, magic, and the great battles of the human heart that transcend time and space, these stories remind adults what it's like to re-enter the worlds of our imaginations.