Researchers say they now know what caused the Hindenburg disaster. So what was it? The simple answer to what took down the Hindenburg is: static electricity.

When the hydrogen-filled blimp was landing in Lakehurst, New Jersey, on May 6, 1937, it suddenly burst into flames and crashed, killing 35 of the 100 passengers and crew on board.

Now a team of researchers at the Southwest Research Institute in San Antonio had concluded that the blimp had become charged with static electricity as the result of an electrical storm.

According to a report in The Independent of Britain, "A broken wire or sticking gas valve leaked hydrogen into the ventilation shafts, and when ground crew members ran to take the landing ropes, they effectively "earthed" the airship. The fire first appeared on the tail of the airship, igniting the leaking hydrogen."