A beacon is a signaling device that emits light, sound, or radio waves to guide or warn people. Commonly used in navigation, beacons help ships and aircraft find safe routes, especially in poor visibility conditions. They can be found on lighthouses, buoys, and even in modern technology like GPS systems. In addition to navigation, beacons are also used in various applications such as emergency alerts and location-based services. For example, Bluetooth beacons can send notifications to smartphones when users are nearby, enhancing the shopping experience or providing information in museums.