Many people who visit Japan make a pilgrimage of sorts to this museum in Hiroshima. I visited the museum 30 years ago, and then once again very recently.
The museum itself has become a bit more sophisticated over the years, doing a superb job (if I can even say that) of showing how horrible it was for the people of Hiroshima to experience the first-ever atomic bombing. War is, of course, hell for all that experience it. And this is how I approached the viewing of this museum. It is not a pleasant experience, but is not intended to be.