lighthouses

Lighthouses are towers or structures built to emit light and serve as navigational aids for maritime pilots. They mark coastlines, hazards such as rocky shores, reefs, and sandbars, and help vessels determine their position and course, especially at night or in poor visibility.

A typical lighthouse consists of a tall support structure topped by a lantern room that houses the light source and lenses. Historically, the light came from open flames or oil lamps, later replaced by kerosene, acetylene, and electric bulbs. The illumination is amplified by a lens system, notably the Fresnel lens, which focuses and projects light over long distances. In modern times, light sources are often LEDs, sometimes powered by solar arrays and connected to automatic control systems.

Lighthouses are maintained as aids to navigation by coast guards or maritime authorities. Most have been automated since the late 20th century, removing the need for resident keepers. In addition to the light, many structures emit fog signals, and some broadcast radio or AIS signals to aid navigation in poor visibility.

Each lighthouse is designed with a characteristic appearance: the color, the height, the type of light, the duration and pattern of flashes (the characteristic), and the nominal range. These attributes allow mariners to identify their location on nautical charts.

Preservation and heritage value: many lighthouses are protected as historic structures, museums, or tourist attractions. They symbolize maritime history, and efforts are made to restore and conserve endangered stations.