Modern Marvels: They are among the most romantic machines ever built, enormous craft held aloft by lighter-than-air gas trapped beneath their vast skins. In the 20th century, they have played a vital role in war, transportation and commerce and been involved in one of the most famous tragedies of all time. This episode tells the story of the inventors and innovations behind these fascinating flyers. Discover what distinguishes a blimp from a balloon from a zeppelin, and watch the footage of the Hindenburg's fiery destruction in New Jersey. Find out how the lessons learned during the heyday of lighter-than-air travel are sewing the seeds for a renaissance today and go aboard the new breed of Zeppelin that is once again taking to the skies over Europe.