As far as this event contributed to the end of WWII.
The event that officially marked the end of World War I was the Treaty of Versailles. It was signed in a railroad car on June 28, 1919.
they just did:p
World War I
World War II brought the end of colonialism.
Germany signed the Treaty of Versailles, resulting ini peace at the end of World War 1.
The atomic bomb
the atomic bomb
World War II.
World War 1
The dropping of the Atomic Bombs was considered the beginning of the end of World War 2. It did motivate Emperor Hirohito to surrender.
mabe
That was the beginning for the US. The end was dropping the A-bombs.