The bicycle is a human-powered, two-wheeled vehicle that can be used for recreation, transportation, or exercise. It has a frame with two wheels attached to a crank, which in turn are connected to a chain and crankarms. The pedals are located on the front of the frame, where a rider can easily reach them with their feet. A bicycle is the most common mode of transportation in much of the world, and it has become an important sport and leisure activity. It also has a number of health and fitness benefits.

The word bicycle comes from the French phrase “bicyclette,” which means two-wheeled machine. Its etymology highlights the fact that a bicycle was the first vehicle to allow a rider to lift their feet completely off the ground. The invention of the bicycle radically changed human mobility and opened up new opportunities for recreational activities and transportation.

Around the turn of the 20th century, bicycles reduced congestion in crowded city tenements by making it possible for working people to commute to jobs outside the city. They also allowed people to explore the countryside, and they were three times more energy efficient than walking or riding a horse. Almost anyone could learn to ride, and they became wildly popular. The sultan of Zanzibar, for example, took up cycling and bought bicycles for his whole harem.

Bicycles can be modified with a variety of accessories, such as baskets, carriers, and trailers. They can also be fitted with pegs to facilitate tricks and stunts, or a specialized saddle for racing or endurance riding. Families often add rear-mounted child seats or a hitch to tow a cargo trailer for transporting children and equipment.

A bicycle turns the energy from a person’s body and movement into kinetic energy, which causes it to speed up as it moves. A person’s legs provide most of the energy to make a bicycle move, although some of it is generated by the crank arms and chain.

Several studies have shown that cycling is associated with improved health and lower mortality rates. It is especially effective in lowering blood pressure and cholesterol, and it can reduce the risk of osteoporosis by building strong bones. In some cases, it may even be more effective than weight loss programs or drug therapies for depression and anxiety.

The bicycle can be a dangerous vehicle, and it is essential to follow safety rules. Wearing a helmet and bright clothing is recommended. It is also a good idea to have a rear light and reflectors on the bike for visibility at night or in poor weather conditions. It is also important to choose a bicycle that fits, and it is important to maintain the brakes regularly. Finally, it is a good idea to practice basic skills before using the bike on public roads. People who use a bicycle for transportation should always obey traffic signals, and they should wear a reflective vest or jacket when travelling in groups.