The first national mountain bike championships were held in 1983 in the USA. But the sport quickly grew in popularity in Europe and Australia. The first mountain bike World Championships, recognised by the International Cycling Union (UCI), were organised in 1990. Olympic recognition followed and mountain biking made its debut as an Olympic discipline at the Atlanta Games in 1996, with a cross-country event for men and women. The programme has remained unchanged ever since. It was in 2008 in Beijing that BMX made its debut on the Olympic programme. BMX is one of the fastest and youngest cycling disciplines. Its principle is simple: eight riders compete on a track filled with jumps, tight bends and obstacles.