A siren is a loud warning device used to alert people to emergencies or dangers. It produces a high-pitched sound that can be heard over long distances. Sirens are commonly found on emergency vehicles like ambulances, fire trucks, and police cars, as well as in public warning systems for natural disasters. Siren alarms can vary in tone and volume, depending on their purpose. They are often used in conjunction with visual signals, such as flashing lights, to grab attention. In many areas, sirens are tested regularly to ensure they function properly during real emergencies.