LZ 130 Graf Zeppelin II

The LZ 130 Graf Zeppelin ΙΙ was the last Zeppelin built in the time between World War 1 and World War 2. Built from the same blueprints as its sister the LZ-129 Hindenburg, in October, 1937, LZ-130 was modified to use helium after the LZ-129 Hindenburg crash, delaying her first flight. Because helium provides less lift than hydrogen, LZ-130’s passenger capacity was reduced from the 72 carried by Hindenburg to just 40. 
Helium is rare and expensive, so the airship was also modified to not leak helium. However, the United States refused to sell any helium to Germany, so the airship was filled with hydrogen anyway.