In the Museum's Pioneers of Flight gallery is a model of the colorful Montgolfier balloon, on which the first untethered hot-air balloon flight was made in 1783. Just outside the Museum Store on the first floor is a model of the Hindenburg. Its fiery crash in 1937 abruptly ended the era of the huge hydrogen-filled airships. Although hydrogen is even less dense than helium, it is extremely flammable. |