A bicycle, also called a cycle or bike, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.

When the geologist Peter Wampler first went to Haiti, in 2007, he didn't expect to see many trees. He had heard that the country had as little as 2 percent tree cover, a problem that exacerbated drought,