After the defeat of Germany in World War II, American turned its full attention toward defeating Japan. Given the religious and militaristic Japanese culture, America struggled to dislodge Japan from its many occupied territorial possessions. However, with sheer willpower, America pushed Japan back onto its home islands, at which point America had to contemplate an invasion of Japan itself. American strategists estimated that an invasion of Japan might cost as many as a million American lives. With this possibility, President Truman sought an alternative. Throughout the course of the war, America had been working on a secret super weapon, the atomic bomb. This weapon was designed to destroy an entire city with one bomb, and cause such fear that an enemy would immediately surrender upon its threat of use. In order to demonstrate the effectiveness of this weapon to Japan, American dropped an atomic bomb on the Japanese city of Hiroshima on Aug 6, 1945, at 8:15 AM, and the city was instantly destroyed. There were approximately 146,000 casualties as a result of this one bomb. America then sent an ultimatum to Japan that anything short of unconditional surrender would result in another bombing. When Japan failed to surrender, America dropped a second weapon. On August 9th at 11:02 AM, this second weapon destroyed the Japanese city of Nagasaki, with a total of approximately 80,000 casualties. After this, Japan surrendered, and World War II came to an end. The beginning of the nuclear age was a significant factor in the eventual Cold War, which would shape world events for around the next fifty years.