One of the most memorable lines in the John le Carré masterpiece, Tinker, Tailor, Soldier, Spy, is a description of the character Jim Prideaux as a young man at Oxford: “By the by, he is virgin, about eight feet tall, and built by the same firm that did Stonehenge.” Right there you have it—stark, strong, pure, primal. Stonehenge, the massive stone enclave in Wiltshire, England, is possibly the world’s most famous prehistoric monument. Made of sarsens and bluestones, it was pulled together around 2,500 B.C. What was the purpose of Stonehenge? The debate remains alive among historians and citizens. In this virtual tour, you can step through the hallowed grounds, and perhaps come to your own conclusions. —E.C.