All the world championship events, except team time trials from 2012, are ridden by national teams, not trade teams such as in most other major races. The winner of each category is entitled to wear the rainbow jersey in races of that category (either mass start or time trial) until the next championships.
The first world championships took place in 1921, though the only event that was contested was the Men's Road Race for Amateurs. The first professional world championship took place in July 1927 at the Nürburgring in Germany where ItalianAlfredo Binda won the professional men's race and BelgianJean Aerts won the men's amateur race. The women's road race was introduced in 1958. A men's team time trial, contested by national teams, was introduced in 1962. Beginning in 1972, the team time trial was discontinued in Olympic years only. Individual time trials in all categories were added in 1994, which was also the last year for the original incarnation of the men's team time trial. In 2012, the men's team time trial was reinstated, and a women's team time trial added to the program; both are contested by trade teams.
Until 1995, there were separate races for male professional and amateur riders. In 1996, the amateur category was replaced with a category for men under-23 years old with the professional category becoming an open (later elite) category.
Since 1995, the race has been held towards the end of the European season in late September, usually following the Vuelta a España. Before that, the event had always been a summer race, held in late August or the first week of September (with the exception of 1970, when it was a mid-season summer event).
The world championships are located in a different city or region every year. The event can be held over a relatively flat course which favors cycling sprinters or a hilly course which favors a climbing specialist or all-round. In each case the course is usually held on a circuit of which the riders complete multiple laps.