A half-pipe is a U-shaped structure commonly used in extreme sports like skateboarding, snowboarding, and BMX biking. It consists of two sloped sides that rise from a flat bottom, allowing athletes to gain speed and perform tricks by riding up and down the walls. The design enables smooth transitions and aerial maneuvers. Half-pipes can vary in size and material, with some made of wood for skateboarding and others made of snow for winter sports. They are often found in skate parks or at snow resorts, providing a safe environment for athletes to practice and showcase their skills.