For other uses, see Bicycle (disambiguation).
This article uses American English. See talk page for more
information.
The bicycle, cycle or bike, is a pedal-driven, human-powered vehicle
with two wheels attached to a frame, one behind the other.

First introduced in 19th-century Europe, bicycles now number
approximately one billion worldwide,[1] providing the principle means
of transportation in many regions. They also provide a popular form of
recreation, and have been adapted for use in many other fields of
human activity, including children's toys, adult fitness, military and
police applications, courier services, and cycle sports.

The basic shape and configuration of a typical bicycle has hardly
changed since the first chain-driven model was developed around 1885,
[2] although many important details have been improved, especially
since the advent of modern materials and computer-aided design. These
have allowed for a proliferation of specialized designs for particular
types of cycling.

The bicycle has had a considerable effect on human society, in both
the cultural and industrial realms. In its early years, bicycle
construction drew on pre-existing technologies; more recently, bicycle
technology has, in turn, contributed both to old and new areas.

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