Mysterious monoliths, Avebury, England. Stonehenge gets all the press, but the massive earthworks and stoneworks at Avebury are, to my mind, even more impressive. Dating back to around 2,600-2,500 B.C. and extending over 28 acres, it is the largest known stone circle in the world.

Unlike Stonehenge, here there are no fences, no guards, no audio guide rentals or souvenir stands. It's just green hills and meadows, big stones, and a palpable sense of ancient mystery and sacredness.