1. The Second World War Ends: The Manhattan Project and The Defeat of Japan

2. Today, we will look at:  The development of nuclear weapons  The Pacific War  The surrender of Japan

3. The Manhattan Project

4. As the Nazis gained power across Europe, many scientists, especially of Jewish background, began fleeing to the United States Among these scientists were Albert Einstein, Enrico Fermi and Nils Bohr; all of whom had done extensive nuclear research

5. Once the United States was at war, these scientists told US President Roosevelt about the possibilities of nuclear weapons Roosevelt was told that Nazi Germany might already be building such a weapon, and decided that the United States should develop the technology as well

6. Under extreme secrecy, the “Manhattan Project” began, with the goal of producing a nuclear weapon for the United States The Project was housed at Oak Ridges Tennessee, employing some of the greatest scientists in the world The necessary research and production of a usable bomb took nearly 3 years The total estimated cost of the project was $20 billion

7. By the early summer of 1945, three usable nuclear bombs had been produced One was intended for testing, while the other two would be reserved for military use The world’s first nuclear detonation took place on 16 July 1945 at Los Alamos, New Mexico

8. The “Trinity” Test: 16 July 1945 5:29 A.M. “If the radiance of a thousand suns Were to burst at once into the sky, That would be like the splendour of the Mighty One... I am become Death, The shatterer of Worlds.“ -J. Robert Oppenheimer, Project Supervisor “Now we’re all sons of bitches” -Ken Bainbridge, Test Director

9. Meanwhile, in the Pacific Ocean…

10. Since 1941, The United States had been at war against Japan The US strategy was called “Island Hopping”, literally taking back one island at a time from the Japanese Each island required a major battle, each taking the lives of thousands of American soldiers

11. The Americans realized that many Japanese soldiers were willing to commit suicide to assist their country Quite often, US Navy ships came under attack from “Kamikaze” or suicide pilots

12. The battles for Iwo Jima (in February 1945) and Okinawa (April 1945) had cost nearly 20 000 American lives, and tens of thousands more injured With these losses in mind, US leaders were looking for a way to avoid an invasion of the Japanese “Home Islands” while still forcing a Japanese surrender

13. On 12 April, 1945, President Roosevelt died suddenly, and Harry S Truman became president of the United States It was only then that Truman was made aware of the Manhattan Project, and of the existence of the Nuclear Bombs Once the first bomb had been successfully tested, Truman faced a decision about the best way to end the war

14. Truman’s moral dilemma: Is it better to risk up to 1 million American lives in an invasion of Japan to end the war, OR, use a new type of weapon with enormous destructive power whose effects are not fully known or understood?

15. Truman elected to make use of the nuclear weapons that were now ready Two target cities were selected by the US military: The cities of Hiroshima and Nagasaki The Japanese government was informed that the US possessed a new type of weapon that could destroy entire cities The Japanese were offered a choice: Surrender unconditionally or face the use of these new weapons The ultimatum was rejected by Japan

16. Hiroshima: 6 August 1945 One of the available nuclear bombs, nicknamed “Little Boy” was loaded into a US Air Force B-29 bomber Shortly before 9:00 am, the bomb was dropped on the city of Hiroshima

17. Hiroshima After the Bomb Nearly 200 000 people were killed in the bombing. Most of the city of Hiroshima was destroyed Many people who survived the bombing would suffer from radiation poisoning over the coming years

18. After Hiroshima had been bombed, the Japanese government was given another ultimatum: Surrender or face another nuclear bombing This warning was also ignored On 9 August 1945, a second nuclear bomb, nicknamed “Fat Man” was dropped on Nagasaki

19. On 14 August 1945, the Japanese government was prepared to surrender to the Allies The formal surrender of Japan was signed on 2 September 1945, on board the US battleship, USS Missouri This ended the Second World War, 6 years and 1 day after it had begun