How did th zeppelin blow up?

Zeppelins used hydrogen for buoyancy because it is much lighter than air - hydrogen has a lifting capacity about seven times greater than that of the next lightest lifting gas helium, at the expense of being highly flammable. Most Zeppelin disasters, such as the LZ 129 Hindenburg in 1937, came as a result of hydrogen fires breaking out after damage (usually to the gas bags) during inflation or, during landing or mooring.