In this alternate universe that is. In our reality, Little Boy went down in a blaze of glory decimating Hiroshima and showing the true military might of the United States of America.
In alternate history land, Little Boy is the name of the (actual) twin bombs Big Boy and Little Boy. Big Boy was used to put an end to World War 3 by the Axis powers on the Communist States of the Americas. Only one bomb was needed, so the brother was put on display in Vienna. It’s still very active and ever decade or so someone tries to steal it, or detonate it. Luckily, nothing dangerous has ever happened with it. Only some graffiti by the pacifists.
Still, today marks the 70th anniversary of the entry into the Nuclear Age in both realities. In a 17th distant reality, the world has been a nuclear power for decades, but we’re not talking about that reality, only this one, the 3rd one from the main one of our current one.