What Happened To Botmetro What Happened To The Rest Of The World In Fallout?

What happened to the rest of the world in Fallout? - what happened to botmetro

I've never really not a lot of attention in the first game and really can not find a general idea of what is in the world. Because they say that the community does not like the desert, but full of the war. And the next Fallout: Vegas Vegas seems not yet been rebuilt or destroyed everything. But the nurse zeta in Fallout 3, the world has been destroyed and irradiated.