Panzer VIII Maus

Panzerkampfwagen VIII Maus (Mouse) was a German super heavy tanks completed in late 1944. It is the heaviest fully enclosed armoured fighting vehicle ever built. Only two hulls and one turret were completed before the testing grounds were captured by the advancing Soviet forces. An incomplete tank was captured by British forces.
These two prototypes – one with, one without turret – underwent trials in late 1944. The complete vehicle was 10.2 metres (33 ft 6 in) long, 3.71 metres (12 ft 2 in) wide and 3.63 metres (11.9 ft) high. Weighing 200 metric tons, the Maus's main armament was a 128 mm KwK 44 L/55 gun (55 calibers long barrel), based on the 12.8 cm Pak 44 anti-tank artillery piece also used in the casemate-type Jagdtiger tank destroyer, with an added coaxial 75 mm gun. The 128 mm gun was powerful enough to destroy all enemy armored fighting vehicles at close or medium ranges, and even some at ranges exceeding 3,500 metres (3,800 yd).
The principal problem in the development of the Maus was finding a powerful enough engine for its weight that could be carried in the tank. Though the specification called for a maximum speed of 20 kilometres per hour (12 mph), no engine was found that could propel the prototype at more than 13 kilometres per hour (8.1 mph) under ideal conditions. The weight also made it impossible to cross most bridges; it was intended to ford or submerge and use a snorkel to cross rivers.
It was intended to punch holes through enemy defences whilst taking almost no damage to any components. 5 were ordered, however only 2 hulls and one turret were completed before the advancing allies found them. Very few of Hitler's generals thought that the Maus would have been any use.

The working Maus prototypes remained at Kummersdorf after being tested at Böblingen. Maus V2 was ordered to Wünsdorf to protect the OKH, Probably 205/1 was ordered there, too, as support for the 205/2 if it drove into mud or to help with diving through rivers (where it would have served as generator unit for 205/2). 205/2 ended at the Hindenburgplatz, in front of the bunker Maybach I, where it was destroyed by placing charges in the engine and fighting compartments. Because it had ammunition stowed under the turret, it was damaged more extensively than 205/1, with the turret being more or less intact. Maus V1 didn't reach this area. It is unknown if the V2 actually fought or not.
After the war, the Soviet Commander of Armored and Mechanized troops ordered the hull of V1 to be mated with the turret of V2. The Soviets used six German FAMO-built 18t German half-tracks, the largest half-track vehicles that Germany built in the war years, to pull the 55 ton turret off the destroyed hull. The combined V1 hull/V2 turret vehicle was completed in Germany and sent back to the USSR for further testing. It arrived there on May 4, 1946. When further testing was completed the vehicle was taken over by the Kubinka Tank Museum for storage where it is now on display.

Mickey MAUS at Kubinka Tank Museum