The world has been here for billions of years and it will go on for many more!!!!
I presume you mean WW2 not 11, but i brought an end to the great depression
The atomic bomb
World War II brought the end of colonialism.
Treaty of Versailles
The Treaty of Versailles.
World War 2 brought about a lot of migration to and from war town areas. The end of the war brought a baby boom to America from returning soldiers and citizens celebrating the end of the war.
I'm not sure
Another world war
Aliens brought life to Earth. The end.
World War I
World War II (by Solomon Zelman)
That was the beginning for the US. The end was dropping the A-bombs.