Stonehenge is an ancient monument on the Salisbury Plain in
Wiltshire. It consists of a group of huge, rough-cut stones, including some that are of a kind only found in Western Wales, about 300 miles distant. No one knows exactly who placed them in their present location. It is estimated that they are 3500 year old or more. An earth wall about 320 feet in diameter surrounded the monument. Thirty blocks of grey sandstone, each standing about 13.5 feet above the ground and weighing an average of 28 tones, stood in a circle about 97 feet in diameter. A continuous circle of smaller blocks stood on top of them.
An inner circle consisted of some 60 blue stones. At the very center was a flat sandstone block 16 feet lock, which probably served as an altar. A stone marker 80 yards east of the altar was set to cast a shadow on it at dawn of the summer solstice, about June 21.
