A unicycle is a one-wheeled vehicle that is powered by the rider's balance and pedaling. Unlike bicycles, which have two wheels, unicycles require more skill to ride because the rider must maintain balance on a single wheel. They are often used for fun, exercise, or even performance in circus acts. Unicycles come in various styles, including freestyle for tricks, mountain unicycles for off-road riding, and giraffe unicycles, which are taller and used for stunts. Learning to ride a unicycle can be challenging, but many find it rewarding and a great way to improve balance and coordination.