Navis Neptun 1/1250 21N SMS Mackensen, the last of the German WW1 Battlecruisers to float
Although none of the class were ever completed, Mackensen herself was launched and moored next to the incomplete Greek Battlecruiser, Salamis. Eventually both were scrapped.
The design was said to have formed the basis for the WW2 Scharnhorst & Gneisenau.