A barrel organ is a mechanical musical instrument that produces sound by turning a cylinder covered with pins. As the cylinder rotates, the pins pluck the metal reeds or strike the pipes, creating music. Barrel organs are often found in public spaces, played by street musicians or used in fairs and festivals. These instruments have a long history, dating back to the 18th century, and are sometimes associated with carnivals and street performances. They can play a variety of tunes, from classical pieces to popular songs, and are often decorated with colorful artwork to attract attention.