How the War Began and Ended
World War 2 is said to have begun on September 1, 1939, with an invasion in Poland by Germany, even though the Empire of Japan was already at war with the Republic of China.
When the first bomb was dropped on August 6,1945 it was dropped over the Japanese city of Hiroshima. The first atomic bomb was named "Little Boy". Three days later, on August 9, another bomb was exploded over Nagasaki, Japan this bomb was named "Fat Man".
On August 14, 1945 Japan surrendered, this officially marked the end of World War 2. On September 2, 1945 the Japanese signed surrender terms on board the USS Missouri.
The entire timeline of World War 2 can be found below.