I. On Salisbury Plain in the south of England lies Stonehenge, the most famous of all megalithic sites. Stonehenge is unique among the monuments of the ancient world. Isolated on a windswept plain, built by a people with no written language, Stonehenge challenges our imagination. The imposing stone circle is located near the top of a gently sloping hill on Salisbury Plain about thirty miles from the English Channel. The stones are visible on the hills for a mile or two in each direction. Stonehenge is one of more than fifty thousand prehistoric "megalithics" in Europe. As you get closer to Stonehenge, the forty giant stones seem to touch the sky. Most of the stones are twenty-four or more feet high. Some stones weigh up to forty tons. Others are smaller and weigh only five tons. At first glance, the stones may appear to be a natural formation. But a closer look shows that only human imagination and determination could have created Stonehenge.II. Today's Stonehenge appears very different from the Stonehenge of yesteryear. Wind and weather have destroyed a small part of Stonehenge over the centuries. People have destroyed much more. Today, less than half of the original stones still stand as the builders intended. Many of the once upright stones lie on their sides. Religious fanatics, who felt threatened by the mysteries posed by Stonehenge, toppled many of the standing stones. They knocked over some of the huge stones, which then shattered; they buried others. Other stones were "mined" over the centuries as free building material and transported away. Even in this century, visitors have come with hammers to carry away a fragment of stone.III. Only in recent years have the stones been protected from the huge numbers of people who see them every year. No one can wander among the stones anymore. Hundreds of thousands of visitors have done too much damage, intentional or otherwise. Today tourists are even prevented from walking among the stones for fear that the millions of footsteps every year could make them unstable.IV. The 12th century English writer and historian, Geoffrey of Monmouth, first recorded Merlin's building of Stonehenge in his famous book History of the Kings of Britain. Geoffrey claimed that his book was a translation of "a certain very ancient book written in the British language". However, no other scholar or historian knows of the existence of such a book. According to Geoffrey, the large stones were brought from Ireland to England to mark the burial place of a group of slain British princes..