Athens, 21 August 2004, Games of the XXVIII Olympiad. Women's track cycling Leontien ZIJLAARD-VAN MOORSEL of Netherlands competes during the individual pursuit event at the Olympic Velodrome. Credit: Getty Images/Jamie Squire

Bicycles were first developed in 1817 and have long since been used as a form of transport. Originally, the front wheel was much larger than the rear wheel, and the rider was elevated a great deal, making them difficult to control and very dangerous. In 1885, J.K. Starley of England devised the more modern bike with a chain and gearing to allow the wheels to be of equal size. Although bicycle races had been held on the old "penny farthings", the new bikes stimulated the growth of bicycle racing as a sport.

Cycling at the Olympics features four exciting disciplines: road, track, mountain biking and bmx.

(BOCOG)