Events leading up to the Atomic Bomb

This timeline is about the key events that made the United States want to bomb Japan and the things that both sides did to each other.


Bataan Death March

04/03/1942 - 04/04/1942

The Bataan Death March was when Japan captured about 70,000 United States Troops stationed in the Philippines. They were forced to walk about 100 miles in very harsh conditions (little food/water and very crowded). Many died before finishing and the march showed how cruel Japan really was.

Island Hopping Campaign

01/01/1944 - 2/01/1945

Throughout 1944 and early 1945, the United States had been capturing many islands off the shore of Japan. They had captured Iwo Jima, an island 700 miles south of Tokyo. They had turned their attention toward Okinawa. Japan saw this as their last chance. Japan had been ordered to fight to the death for the rest of the war.


08/14/1945 - 08/15/1945

The two deadly atomic bombs forced Japan to surrender because they had lost over 150,000 people.


Pearl Harbor

12/07/1941 - 12/08/1941

This was the first attack on the United States by Japan. This caused us to get into a war with Japan and join World War II.

Bombing of Hiroshima (Atomic Bomb)

08/06/1945 - 08/07/1945

The first atomic bomb had been dropped on the port city of Hiroshima. This bomb killed 70,000 people instantly and was code named "Little Boy." One-third of the people killed at first were military. The bomb had destroyed everything within a 2 mile radius and about 4 square miles. It also caused radioactive "black rain" killing more people.

Bombing of Nagasaki (Atomic Bomb)

08/09/1945 - 08/10/1945

The bombing of Nagasaki was even worse than the first bomb. It killed over the number killed from the first one instantaneously. The initial fireball had a thousand yard radius. It was code named "Fat Man" and destroyed 18,000 homes. Like the first one, the bomb caused radioactive "black rain" which took more peoples lives.


Battle of Coral Sea

05/15/1942 - 05/16/1942

The war itself was not that significant. However the reason it leads up to the atomic bomb is because after the battle, the United States started turning into offensive after being defensive for the beginning of the war.

Battle of Tarawa

09/15/1943 - 09/16/1943

At this time the United States was offensive in their battle tactics. However, this would come with a cost because Japan was also offensive. Thousands had already died in battle from both sides. The Battle of Tarawa was one of the bloodiest battles in the whole war. Out of 5000 people on Japans side, only 17 survived and over 1000 U.S Troops died in battle.

Progression of Atomic Bomb


1939 - 1940

This is about the time the atomic bomb was starting to be made.


06/01/1945 - 06/02/1945

The atomic bomb was in consideration. The President, Harry S. Truman, wanted to invade Japan or use the atomic bomb. He knew the atomic bomb was very powerful. If he invaded Japan, it would most likely be very costly because they had been ordered to fight to the death. Him and the Intern Committee had to make a decision.


07/26/1945 - 07/27/1945

At this time the atomic bomb was approved for use.