For thousands of years, humanity has been fascinated by the notion that man will one day travel through time. But what if time travel has already taken place? Some of the world's greatest scientists firmly believe that this mind-bending feat is theoretically possible. So, is it really too far-fetched to believe that certain people may have managed to journey through the fabric of time, whether by design... or perhaps, by accident?

During the Middle Ages, the Vikings were infamous for being a bloodthirsty band of seafaring warriors. But while we're all aware of the Vikings' notorious reputation, historians are learning surprising new things about this Norse society. Is it possible that they were not the savage brutes we think of today--but rather, a highly advanced civilization?