Roter Sand is a lighthouse in the North Sea, in the Weser estuary. It entered service in 1885. The light was deactivated in 1986 but the tower still serves as a day beacon. Roter Sand Lighthouse was the first building ever to be erected directly on the sea floor. On 1 October 2010, the structure was awarded the title "Historical Monument of Engineering in Germany" (Historisches Wahrzeichen der Ingenieurbaukunst in Deutschland) by the Federal Chamber of Engineers. From Wikipedia
