Has the Holy Grail been in America all along? In 1898, a Minnesota farmer clearing trees from his field uprooted a large stone covered with mysterious runes that tell a story of land acquisition and murder. The stone allegedly dates back to 1362. Initially thought to be a hoax, new evidence suggests the find could be real, and a clue that the Knights Templar discovered America 100 years before Columbus, perhaps bringing with them history's greatest treasure...the Holy Grail. Follow the clues as experts use erosion studies on the rune stone and match symbols in Templar ruins all over Europe to support this theory. Stones with similar markings have been found on islands across the Atlantic Ocean, and in Massachusetts and Rhode Island. Is it possible the Knights Templar, long thought to have been massacred, escaped on an incredible journey and were leaving clues to the whereabouts of the stone? Find out in the HISTORY two-hour special, Holy Grail in America.