About the Subject (from Wikipedia)
“A German World War II super-heavy tank completed in late 1944. It is the heaviest fully enclosed armored fighting vehicle ever built. Five were ordered, but only two hulls and one turret were completed, the turret being attached before the testing grounds were captured by advancing Soviet military forces.
he principal problem in the design of the Maus was developing an engine and drivetrain which was powerful enough to adequately propel the tank, yet small enough to fit inside it. The Maus was too heavy to cross bridges. As a result, an alternative system was developed, where the Maus would instead ford the rivers it needed to cross.