British scientists say they have solved a mystery involving Stonehenge, the world-famous stone monument in Wiltshire, England. The scientists reported this week that they have identified where many of Stonehenge’s large stones, called megaliths, came from. Thousands of years ago, people used such stones to build markers, monuments, and other structures. The researchers said part of one megalith helped solve the mystery. The small piece of stone had been kept in the United States for over 40 years. Chemical testing suggests that most of Stonehenge’s megaliths, known as sarsens, came from an area called West Woods. It is about 25 kilometers away from the ancient monument, the researchers said on Wednesday.