Cycling is the use of bicycles, or - less commonly - unicycles, tricycles, quadricycles and other similar wheeled human powered vehicles (HPVs) as a means of transport, a form of recreation or a sport. It is done on roads and paths, across open country or even over snow and ice (icebiking).
Bicycles, the most common form of cycle, were introduced in the 19th century and now number about one billion worldwide. They are the principal means of transportation in many regions.
