Synopsis: Every year, a million visitors are drawn to the Salisbury Plain in southern England, to gaze upon a mysterious circle of stones. Stonehenge may be the best-known and most mysterious relic of prehistory. Now investigations inside and around Stonehenge have kicked off a dramatic new era of discovery and debate. Who built Stonehenge? What was its purpose? How did prehistoric people quarry, transport, sculpt, and erect the giant stones? A new generation of researchers are tackling these questions.