As a matter of fact, bicycles are one of the oldest and most refined technologies available to us.
Bicycles can hardly be considered an old technology. While Da Vinci had already sketched some designs in the late 15th century [1], the first prototypes could not be built before the early 19th century.
The first recognizable version of the current chain-driven models was only produced in 1885. [2]
The chain-driven bicycle is not as simple as it looks.
[1] http://www.ltolman.org/davinci.htm [2] http://en.wikipedia.org/wiki/Bicycles