faced with large amounts of synthetic production that began with plants coming on line starting in 1942, and it used blockade breakers to get the 10-15% of natural rubber the plants needed for the expensive synthetic rubber process. In total, as Hitler's generals had warned him, few raw materials were gained from the Soviet invasion. Over the entire four years of the war after Barbarossa, Germany managed to squeeze out only 4.5 billion Reichsmark of Soviet goods in total from occupied Soviet territories, a fraction of what Hitler thought it could gain. Stalin was confident of victory even as Hitler's troops pressed the outskirts of Moscow in the fall and winter of 1941. In September 1941, Stalin told British diplomats that he wanted two agreements: (1) a mutual assistance/aid pact and (2) a recognition that, after the war, the Soviet Union would gain the territories in countries that it had taken pursuant to its division of Eastern Europe with Hitler in the Molotov–Ribbentrop Pact. The British agreed to assistance but refused to agree upon the territorial gains, which Stalin accepted months later as the military situation deteriorated somewhat in mid-1942. In November 1941, Stalin rallied his generals in a speech given underground in Moscow, telling them that the German blitzkrieg would fail because of weaknesses on the German rear in Nazi-occupied Europe and the underestimation of the strength of the Red Army, such that Germany's war effort would crumble against the British-American-Soviet "war engine". Fending off the German invasion and pressing to victory in the East required a tremendous sacrifice by the Soviet Union. Soviet military casualties totaled approximately 35 million (official figures 28.2 million) with approximately 14.7 million killed, missing or captured (official figures 11.285 million). Although figures vary, the Soviet civilian death toll probably reached 20 million. Millions of Soviet soldiers and civilians disappeared into German detention camps and slave labor factories, while millions more suffered permanent physical and mental damage. Economic losses, including losses in resources and manufacturing capacity in western Russia and Ukraine, were also catastrophic. The war resulted in the destruction of approximately 70,000 Soviet cities, towns and villages. Destroyed in that process were 6 million houses, 98,000 farms, 32,000 factories, 82,000 schools, 43,000 libraries, 6,000 hospitals and thousands of miles of roads and railway track. Production during the Pact While Germany's population of 68.6 million people was the second largest in Europe, that was