Designed by Count Ferdinand von Zeppelin, the airships were built from a rigid cigar shaped metal structure of circular frames connected by longitudinal beams. This made them strong enough to be fitted with engines and to carry a useful payload. There were steering fins at the rear and gondolas suspended below for the crew and engines. More crew compartments were inside the main frame as well as spaces for cargo and bags that contained the hydrogen gas for lift. The Super Zeppelins, called "X" or L70 type, the Height-Climbers: The largest Zeppelins during WWI represented the "X"-class or L70 Types. These were the LZ-112, LZ-113 and the LZ-114, with the LZ-114 / Dixmude as the biggest of them all.