Modern technology may be the key to unlock hidden secrets about an ancient monument: Stonehenge.
Researchers are using lasers to scan the nearly three dozen stones, or megaliths, that make up the famous circular complex on the Salisbury Plain of southern England.
The vertical stones -- over 10 feet tall and weighing many tons -- form the site that's believed to be nearly 5,000 years old. And nobody is sure why or how Stonehenge was originally built.
"This new survey will capture a lot more information on the subtleties of the monument and its surrounding landscape," said Paul Bryan of English Heritage, an adviser to the British government on historic buildings and monuments.