Credit: University of Manchester Some say King Arthur slayed a giant there. Others say he knelt in prayer and his knee print indentations are forever etched into the stone. But archaeologists are setting out to find out just how big the structure is and what really happened at Arthur's Stone, a 5,000-year-old, Neolithic chambered tomb in Herefordshire, England, near the border of Wales. On July 1, a team of researchers began excavating the site, said Julian Thomas, an archaeology professor at the University of Manchester who is leading the project. They'll be on site for the next four weeks, Thomas...