Grosstraktor
Grosstraktor (German: "large tractor") was the codename given to six prototype medium tanks built (two each) by Rheinmetall-Borsig, Krupp, and Daimler-Benz, for the Weimar Republic, in violation of the Treaty of Versailles. Constructed in secret, they were tested by Reichswehr units at the Kama tank school in the Soviet Union.