The old lighthouses of Nidingen, westcoast of Sweden. The "twin" lighthouses of Nidingen was built in 1832 and then rebuilt 1846.
The island of Nidingen is considered to have had the worlds first "twin" or double lighthouses. This was back in 1624 to separate Nidingen from Skagen and Anholt. At that time the "lighthouses" was made of burning coal on top of two small towers.