A bicycle (also called a bike or cycle) is a two-wheeled steerable machine that is pedaled by the feet of a rider. They are widely used for transportation, recreation, and sport.

In modern times, bicycles have become the primary means of transport for many people worldwide. This is largely because they are cheap, efficient, and environmentally friendly.

They are also a great way to get fit and stay healthy, as they offer a lot of cardiovascular exercise. Plus, they are very easy to ride and don’t require much training or equipment.

Cycling can also help to reduce your stress levels, which can lead to a number of health problems. It can even make you look and feel better in the long run, helping to boost your self-esteem and confidence!

The history of the bicycle is debated. While many historians believe that Leonardo da Vinci designed a bicycle in 1492, there is no documentary proof of this date. Instead, the invention is attributed to a series of inventors who were seeking a means of moving people without the need for a horse.

Early bicycles were a combination of several different forms. For example, the earliest pedal-powered bicycles were steered with the pedals mounted on the front wheel and the handlebars attached to the frame. But, as the bicycle became more sophisticated, gearing was necessary to allow the rider to efficiently use the pedals. This led to the development of a chain drive, which connected the frame-mounted cranks to the rear wheel.

Bicycles are usually accompanied by a seat, or saddle, which is mounted to the bike frame and allows the rider to sit comfortably and steer with their hands. They are often equipped with a rack for carrying gear.

Some bikes have suspension seat posts or springs, which provide comfort and absorb shock, although they can add weight to the bicycle. They also require periodic lubrication and adjustment to keep them running smoothly.

Another popular form of bicycle is the BMX, which features a low-slung front frame and a high-slung rear frame that allows the rider to stand on the bike without having to lean it forwards. These bicycles are not as safe for children to ride as conventional bicycles, but they can be fun for some.

The bicycle’s design has evolved through several changes since the first model was invented in the late 19th century. A number of improvements have been made in recent years, including the design of the bicycle’s frame and wheels.

Cyclists wear luminous clothing to help them be seen on dark or rainy nights, and they frequently carry spare parts, such as tools and shoes. Some cyclists wear helmets, which protect the cyclist’s head from injury when hit by a car or other vehicle.

When a bicycle is used on the road, it must be registered and properly insured to protect the owner from legal liability for personal injuries. This requirement may be voluntary or compulsory, depending on the local government’s policy.