A bicycle is a two-wheeled vehicle that is powered by human pedaling. It consists of a frame, handlebars for steering, pedals for propulsion, and a seat for the rider. Bicycles can vary in design, including types like road bikes, mountain bikes, and hybrid bikes, each suited for different terrains and purposes. Bicycles are commonly used for transportation, recreation, and exercise. They are an eco-friendly alternative to motor vehicles, helping to reduce traffic congestion and pollution. Many people enjoy cycling as a hobby, and it is also a popular activity in events like the Tour de France.