The USS Macon, one of the largest helium-filled airships ever created, crashed into the Pacific Ocean off the coast of California and sank<--!(contemporary artist's rendering of the crash).-->

USS Macon (ZRS-5) was a rigid airship built and operated by the United States Navy for scouting and served as a "flying aircraft carrier", carrying up to five single-seat Curtiss F9C Sparrowhawk parasite biplanes for scouting or two-seat Fleet N2Y-1s for training. In service for less than two years, the Macon was damaged in a storm and lost off California's Big Sur coast in February 1935, though most of the crew were saved. The wreckage is listed as the USS Macon Airship Remains on the U.S. National Register of Historic Places.

Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and Jupiter, because of the very high nuclear binding energy of helium-4 with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are created by nuclear fusion of hydrogen in stars.

An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the surrounding air to achieve the lift needed to stay airborne.