Extreme unicycling involves riding unicycles in dangerous locations like cliffs, rainforests, and steep mountains. The unicycle was invented in 1869 but was first used in circuses in 1881. In the 1980s, some athletes took interest in the unicycle and started practicing new extreme sports like extreme, street, and trials unicycling. Riders compete in events involving different unicycling disciplines like artistic riding, track racing, and marathons. Competitions have rules like starting after a bell and are held every two years.