 Complete the following phrase:  In the First World War, Imperial German submarines had been transported via rail to the Pola Flotilla based in the Adriatic. With Turkey as an ally of the Central Powers, the Imperial German Navy could also access the Black Sea via the Dardanelles and the Bosphorus, where the Constantinople Flotilla was based. In the Second World War, during Operation Barbarossa, the Luftwaffe engaged the Soviet Black Sea Fleet, but at the Romanian 