A blimp is a type of airship that is filled with a lighter-than-air gas, such as helium or hydrogen. Unlike traditional balloons, blimps have a flexible envelope that maintains their shape, allowing them to be steered and controlled. They are often used for advertising, aerial photography, and surveillance due to their ability to hover in one place for extended periods. Blimps are typically powered by engines that drive propellers, enabling them to move forward and change direction. They are distinct from other airships, like Zeppelins, which have a rigid structure. Blimps are popular at sporting events and festivals, where they can provide unique aerial views and promote brands.