Panzer VIII Maus
Panzerkampfwagen VIII Maus ("Mouse") was a German World War II super-heavy tank completed in late 1944. It is the heaviest fully enclosed armoured fighting vehicle ever built. Five were ordered, but only two hulls and one turret were completed before the testing grounds were captured by advancing Soviet military forces.
Tanks in the Soviet Union
By 1935, the Red Army "... possessed more armoured vehicles, and more tank units than the rest of the world combined." But from 1937 to 1941, the Red Army's officer corps, the armour design bureaux, and leadership of the factories were gutted by Stalin's Great Purge. Approximately 54,000 officers were repressed. Military knowledge completely stagnated and armoured vehicle production dropped drastically (though still remaining the world's largest). Training and readiness dropped to very low levels. This repression continued until the eve of the war.