The Graf Zeppelin was a German, hydrogen-filled, passenger airship—the largest built up to that time. It inaugurated transatlantic flight service in 1928, making its first crossing in 111 hours. During its years of service, it completed 590 flights, including 64 to South America, two to the Middle East, and one around-the-world tour. It was retired from service in 1937, when the Hindenburg disaster brought an end to commercial zeppelin travel. Why was the airship destroyed during WWII? Discuss