Stonehenge is probably the world's best-known megalithic site. A megalith is a standing stone monument. Situated on Salisbury Plain in Southern England, it has been associated with all sorts of astronomical and religious myths. On June 21, each year thousands of visitors collect for a festival to mark the summer solstice, or mid-summer.
It consists of a three circles of stone, within each other, surrounded by a circular ditch. The site was built in stages.
The First Stage: 2800 B.C.
The first stage was probably begun in about 2800 B.C. This is the outer, circular ditch, with a raised embankment. It measures about 330 feet across. Just inside the ditch are 56 holes, evenly placed around the circle. They are called Aubrey holes, after a 17th century historian, who discovered them. These holes probably contained wooden posts, which have long since disappeared. A pathway, leading up to and into the circle, was probably built at the same time, but may have been built later.
The Second Stage: 2000 B.C.
During this stage of construction, a double circle of about 60-80 stones was placed in the middle of the circle formed by the ditch. These stones are called "blue stones" and a few remain today. They are the smallest stones used at the site, but they still each weighed about 4 tons. They came from the Welsh mountains. Although no one knows for sure how they got there, it is thought they were transported mostly on barges, using the sea and rivers, and barely had to travel over land at all. For some reason, this circle of stones was never completed and was partly replaced with a horseshoe arrangement of larger stones. The larger stones are called sarsens and are sandstone blocks, from an area about 20 miles from the site. There were ten upright stones, arranged in five pairs, with a huge horizontal stone across each pair. These stones weigh up to 50 tons each, and were transported by land. It is estimated that each stone took 600 men to move!
The Heel Stone
At this time the heel stone was also placed. It is the considered the most important stone at the site, weighing 35 tons. It has a pointed top, and its placement has been the cause of a lot of the theories surrounding the site. During the summer solstice (midsummer day) if you stand in the center of the circle, you will see the sun rise directly over the pointed tip of the heel stone.
The Third Stage: 1800 B.C.
During the third stage the builders built an outer ring of huge sarsens, each weighing about 35 tons. There are 30 stones, and across the top of them all, forming a complete circle, there were horizontal stones.
There have been many theories over the years as to who built the site and why. Probably the most famous one is that the Druids built it as a place of worship. The problem with this theory is that there were no Druids in England at the time it was built, and the Druids preferred places with trees for their worship.
Another theory is that it was some sort of religious site where human sacrifices were made, but this theory is the weakest of all, since no human remains have been found there. There is some evidence that ashes of cremated bodies were placed in the Aubrey holes, but much later than the original time the site was built.
Another, and the best theory, is that it was some sort of astronomical observatory. The sun rises directly over the heel stone on midsummer's day. It is not very likely that this is a coincidence. The problem with this theory is that over the 5000 years that it has stood, mid-summer's day has changed, and so has the position of the sun. However, people have estimated that 5000 years ago, mid-summer's day was June 24, and that the sun would have risen over the heel stone then. Other calculations show that it could have been used to predict solar and lunar eclipses, and perhaps even as a daily calendar.
We will probably never know exactly why the site was built. One thing is certain, though. It was built for an important purpose, since no one would have gone to so much effort just for fun!