Harmaja (Swedish: Gråhara) is an island and a lighthouse outside Helsinki, south of the Suomenlinna sea fortress. The island has been functioning as a landmark since the 16th century. A landmark structure was built on the island in the 18th century and a light house in 1883. The first lighthouse was only 7.3 m high and it soon proved to be too low. In 1900 the height was doubled by creating a rectangular brick building on a granite base. A large foghorn alerted ships in fog and in bad visibility. Harmaja received the world's first directed and undirected radio beacon in 1936. The lighthouse is fully automated today.