Nazi Bomb!
By 
Latest counter-factual at the National Interest:
In the early years of World War II, it looked as if Germany might have the luxury to spend its time developing a new generation of super-weapons. The Nazis haphazardly pursued the idea of building an atomic bomb, with an eye toward eventual conflict with the United States. However, the immediate demands of war, combined with Western Allied sabotage, undercut the program, leaving it at the basic research stage by war’s end.
But what if the Germans had devoted more attention to the program, or had lucked into more substantial breakthroughs? What could the Nazis have done with an atomic weapon?