Fog horns are loud sound signals used primarily in maritime navigation to warn ships of nearby hazards, especially in foggy conditions. They help vessels avoid collisions with land, other ships, or obstacles in the water. Fog horns can be powered by air, electricity, or steam, producing a deep, resonant sound that travels over long distances. These devices are typically installed at lighthouses, buoys, and coastal areas. The sound pattern of a fog horn can vary, with some emitting a continuous blast while others use a series of short and long blasts. Lighthouses often work in conjunction with fog horns to enhance safety at sea.