An aid for
navigation at
sea, a lighthouse is a tower building sending out light from a system of lamps and lenses or, in older times, from a burning fire. If there is no building, but only a fire on top of a hill, that is called a
beacon.
Perhaps the most famous lighthouse of all history is the Lighthouse of Alexandria, built on the island of Pharos? in ancient Egypt. The name of the island is still used as the
noun for lighthous in some languages, e.j. Spanish (faro).