By 1940, Stalin had bled Russia of any potential leaders, and certainly did not want war. He signed a non-aggression pact with Hitler, but this was ruptured after Hitler invaded the Soviet Union. The war casualties were immense: 20 million dead, 25 million homeless, 70,00 cities and villages destroyed. The people were exhausted, but Stalin refused to agree to reasonable peace terms, and after the Potsdam conference, the Cold war began. Stalin died in 1953, regretting nothing, and it took his successors years to free themselves from the system.