A helmet is a protective equipment worn on the head to prevent injuries in activities such as cycling, motorcycling, practicing extreme sports, or working in construction sites. Usually made of materials like rigid plastic, fiberglass, or metal, a helmet is designed to absorb the impact of collisions and protect the skull and brain from severe injuries in case of accidents. It typically features an internal padded structure to cushion the impact and a tough outer covering to provide additional protection. Helmet use is considered essential for personal safety in many activities and is often required by law in certain contexts, such as riding a motorcycle or bicycle on public roads.