The German Naval Memorial at Leboe was originally erected as a memorial for German sailors killed in WW1 but after WW2 was changed to an internationally accepted peace monument. It was wholly privately funded and build on the site of a disarmed coastal battery.
Admiral Scheer dedicated the monument on 31 May 1936. Adolf Hitler was present but didn't speak as Admiral Raeder spoke in his stead. It was largely undamaged during WW2 and was confiscated by British occupation forces. Unlike other military memorials, it was not destroyed as it was accepted as a memorial which did not glorify war but which was intended to pay tribute to seamen who had died for their country.
In 1954 the memorial was returned to the German Naval Association and during the ceremony Otto Kretschmar (the u-boat commander who sank the most tonnage during WW2) dedicated it to all mariners who had lost their lives in both wars and it has remained an international peace monument ever since.
The Laboe memorial:
Part of the memorial wall which depicts the German ships lost during WW1 and 2. This is the WW2 wall and the WW1 wall faces it, giving a stark reminder of the sheer number of ships lost by just one side during the war:
U-boat models:
Bismarck model:
Wilhelm Gusloff model. The greatest loss of life in a single incident when it was sunk by a Russian submarine (estimated loss of over 9000 lives):
