A form of winter-based bicycle racing practised on cross-country courses, in which the cycle may have to be carried rather than ridden across particularly rough terrain. The sport's origins have been identified in France, in the early 20th century, and in the industrial midlands of England in the early 1920s. It became popular in parts of northern Europe, Eastern Europe, and the USA. A first world championship was held in 1925, officially recognized from 1950 by the Union Cycliste Internationale, which recognizes cyclo-cross as one of its disciplines: riders do circuits of 2.5 to 3.5 kilometres that include ‘clearings, roads, country lanes and paths through forests’. Several laps of the circuit are accomplished within the prescribed period of one hour.