Lighthouses are generally built in coastal areas, especially ports and docks.

Because of the lack of sea positioning technology in ancient times, the routes were all along the coast, and the establishment of lighthouses helped ships not lose their way at night.

The most famous lighthouse in ancient times is the lighthouse of Alexandria, one of the seven wonders of the world. It is said that the reason for its establishment is that the ship that the bride of Ptolemy II took hit the rocks and sank.

The lighthouse is 135 meters high. It uses mirrors to reflect sunlight during the day and firelight to indicate it at night. The fuel for the lights is olive oil and wood. The Lighthouse of Alexandria is not only a practical lighthouse but also the essence of architectural art.

Lighthouses are used as navigation aids to mark shorelines, and dangerous objects and turn on lights for conventional navigation.

With the development of modern navigation aids signs are not only limited to lighthouses, but also light boats, light stakes, light floats, and so on.

The identification type is not limited to visual lights, and the development of radio navigation equipment is also changing with each passing day, and even AIS virtual beacons accepted by special radio equipment have appeared.

The functions are basically the same in ancient and modern China and abroad.

However, with the development of science and technology and large-scale ships, many lighthouses with a long history have become scenic spots and historical sites, and gradually lose their role as navigation aids.

As for how to achieve its function, each lighthouse will have its unique light quality color and flashing rhythm to distinguish it from the nearby lighthouses, so that after observing the light quality and rhythm at night, the navigator can compare with the lighthouse marked on the chart.

Compare, identify, and then judge whether your ship's position is yaw and whether it is safe according to the compass bearing relative to the lighthouse. In this way, the lighthouse plays a role in ensuring the safety of ships and assisting navigation.

The lighthouse is a tall tower-shaped building. Lighting equipment should be installed at the top of the tower. The location should be conspicuous, and it should have a specific architectural shape, which is easy for ships to distinguish and becomes one of the highest points in the port.

Since the surface of the earth is a curved surface, the tower body must have a sufficient height so that the light can be seen by long-distance ships, and the general line of sight is 15-25 nautical miles.

But the light should not be too high, so as not to be obscured by clouds and fog at high places. According to the size of the lighthouse and the characteristics of the location, the lighthouse can be guarded or unguarded. Important lighthouses should be guarded.

If someone gets lost while swimming or playing in the sea, he can turn to the lighthouse, because the lighthouse can help people guide the way.

When electricity was not widespread, lighthouses often used fire as the light source, so it symbolized a steady stream of hope and light.