A blimp is a large, balloon-like aircraft that floats through the sky without wings. Blimps are filled with helium, a gas lighter than air, which helps them rise, like a helium balloon at a birthday party but enormously bigger.

You've probably seen blimps floating above sporting events, their sides covered with advertisements or company logos. One famous example is the Goodyear Blimp, which has been flying over football games and other events since 1925. From the ground, blimps look slow and peaceful as they drift across the sky, but inside the cabin hanging beneath the giant gas envelope, pilots carefully control the engines and rudders to steer.

Blimps differ from rigid airships (like the famous Hindenburg) because they have no internal framework. A blimp is essentially a huge balloon with a motor: when the helium escapes, it deflates and collapses. This makes blimps cheaper and safer to operate than their rigid cousins, though they can't carry as much weight or fly as far.