Zeppelins dominated the skies of Europe and America in the 1930s. They were involved in military action. They carried many people across the Atlantic and helped explore the Arctic. They created a global sensation, but their era was short-lived -- eclipsed by airplane technology and one notorious tragedy. More than 70 years later, they are back on track. Airships have been designed and built in Germany, the United States and Russia. The new versions are much smaller than their predecessors. Today they are used for entirely different purposes.