The lasers also showed graffiti and other damage done by 19th century visitors. At that time, people were permitted to remove pieces of the stones. They could pay workmen to break off pieces to take home as souvenirs.

For many years, some people believed that Stonehenge was used as an observatory for watching the skies or a place to worship the sun. Others thought the stone circles formed a calendar. But other theories are gaining support.

Researcher Mike Parker Pearson, for example, says Stonehenge was built to help unite what now is eastern and western Britain. These areas had suffered long years of conflict and battle.

Professor Parker Pearson is with the University of Sheffield. He leads a team called the Stonehenge Riverside Project. The project has been studying the stone circle and places linked to it for almost 10 years.

Professor Parker Pearson says the early people were developing a common culture. Changes in earthenware and ways of life showed that people were traveling. They were learning about cultures other than their own. But the professor’s main idea about the purpose of Stonehenge is that it served as a burial ground.

Some human remains found near the stone circles show physical injury or disease. This helped lead two well-known researchers to propose that Stonehenge was a refuge or shelter for people with health problems.

Archeologists Geoffrey Wainwright and Timothy Darvill proposed that Stonehenge may have served as a place to heal the sick. Like Mike Parker Pearson, the two archeologists have worked for years to try to solve the mysteries of the circles.