Travel to wild and adventurous Wales, U.K., in this three-episode journey. Wales has more castles per square mile than anywhere, and a few of them are explored here. Learn about the Roman history in Wales, with the largest colosseum outside of Rome. See firsthand the ancient history of the British Isles, and descend underground into the Big Pit to learn about the coal and slate mining history of this area. - Traveling in Wales with kids.