Bicycle, usually called bicycle or bicycle, is a kind of monorail vehicle driven by manpower and pedals. Its two wheels are fixed on the frame and one on the other. Cyclists are called cyclists.

Bicycles came out in Europe in the 19th century. By 2003, the world had produced 1 billion bicycles, twice the output of automobiles. They are the main means of transportation in many areas. They also provide a popular form of entertainment and have been used as children's toys, general fitness, military and police applications, courier services and cycling competitions.

Since the first chain driven model was developed around 1885, the basic shape and configuration of a typical upright or "safety bike" have hardly changed. However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have led to a proliferation of specialized designs for many types of bicycles.

The invention of bicycle has a great influence on the society in terms of culture and advanced modern industrial methods. Several components that ultimately play a key role in the development of automobiles were originally invented. These components are used in bicycles, including ball bearings, pneumatic tires, chain drive sprockets and tensioning wheels.

From the beginning to today, bicycles have been and have been used for many purposes. Bicycles are used in a pragmatic way for transportation, bicycle commuting and utility bicycles. It can be used as a "working horse" for postmen, paramedics, police, couriers and general delivery services. The military uses of bicycles include communications, reconnaissance, troop movements, supplies and patrols. See also: Bicycle infantry.

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