RAF reconnaissance photo showing Köln moored in the Fætten Fjord northeast of Trondheim, Norway, 19 Jul 1942, photo 2 of 3.
Köln was a German light cruiser prior to and during World War II, one of three K-Class cruisers named after cities starting with the letter K. This ship was named after the city of Köln (Cologne). The others in her class were the Königsberg and the Karlsruhe. The K-class cruisers were designed in the 1920s and built in accordance to the 6,000 ton limit for cruisers imposed on Germany by the Treaty of Versailles. To stay within this limit, 85% of the ships were welded instead of riveted. This caused problems, as the welding did not withstand the stress of long-term journeys as well as had been hoped.