Stonehenge, the famous stone circle in southern England, has always been a mystery. New research published in Nature gives more details about a big flat stone in the middle, called the “altar stone.” This 16-foot-long (5 meters) in length stone was thought to come from Wales, but it actually came from northeast Scotland. The stone’s special features do not match the Welsh rocks, so scientists now know where it came from. To figure out the stone’s origin, researchers looked at old rock samples from past digs, some dating back to the 1840s. They found that the stone matches rocks from the Orcadian Basin in northeast Scotland, including the Scottish peninsula and the Orkney Islands. This unique “fingerprint” is not found anywhere else in the UK. The stone traveled over 460 miles (740 kilometers), showing that the people who built Stonehenge had advanced skills and strong links with faraway places. Stonehenge, built about 5,000 years ago, was used for ceremonies. Researchers are still studying the altar stone’s role in Stonehenge.