Nautical signals are visual or auditory communications used by ships and boats to convey important information at sea. These signals can include flags, lights, and sound signals, each with specific meanings. For example, the International Code of Signals uses a series of flags to represent letters and messages, allowing vessels to communicate even when they are far apart. In addition to flags, lighthouses and buoys often use colored lights to indicate safe navigation routes or warn of hazards. Sound signals, such as horns or whistles, are also crucial, especially in foggy conditions, to alert nearby vessels of a ship's presence and intentions.