A halfpipe is a U-shaped ramp or channel used in action sports like skateboarding, snowboarding, and BMX biking. Picture cutting a huge pipe in half lengthwise and laying it on its side: you get two steep curved walls facing each other with a flat section between them. Athletes drop in from one side, gain speed crossing the bottom, then shoot up the opposite wall, sometimes launching high into the air to perform tricks before coming back down.

The walls of a halfpipe can range from a few feet tall at a local skate park to over 20 feet at professional competitions. Snowboard halfpipes carved into mountains might be even larger. Riders use the back-and-forth momentum to build speed, going higher with each pass until they're soaring above the edge of the pipe, spinning and flipping before landing back on the curved wall.

What makes halfpipes exciting is how they let athletes combine speed, height, and creativity. A skilled rider doesn't just go up and down; they're constantly adjusting their approach, deciding when to build speed and when to launch into the air for an impressive trick, and aiming to land smoothly and safely.