It is estimated that over 50,000 stone megaliths were
erected in a great arc around the coasts of Europe, from Sweden
and the Shetland Islands in the north to Spain, Portugal and
Malta in the south. No one knows when they were erected, who
erected them, nor for what purpose they were erected. Dating
them has not been easy, as they were cut from stone. Estimates
put them around 4,500 years ago (2,500 BC)
The most famous megaliths are found at Stonehenge.
They are located on the Salisbury Plain in southern England,
a chalk grassland that stretches as far as the eye can see.