A bicycle, or bike, is a pedal-driven, human-powered vehicle

A bicycle, 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 over one billion worldwide,
[1] providing the principal means of transportation in many regions,
notably China and the Netherlands. They are also 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
local police applications, courier services, and cycle sports. The
basic shape and configuration of a typical bicycle's frame, wheels,
pedals, saddle, and handlebars have hardly changed since the first
chain-driven model was developed around 1885[2] , although many
important details have since been improved, especially since the
advent of modern materials and computer-aided design. These have
allowed for a proliferation of specialized designs for individuals who
pursue a particular type of cycling. The bicycle has affected history
considerably, 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 ideas in both
old and newer areas.

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