If you have the opportunity to visit, I recommend Nagasaki over Hiroshima and especially these two places in Nagasaki: Shiroyama Elementary School Nagai Takas

If you have the opportunity to visit, I recommend Nagasaki over Hiroshima and especially these two places in Nagasaki: Shiroyama Elementary School Nagai Takashi Memorial Museum Nagasaki These felt much more personal than anything I saw in Hiroshima and there were zero (other) tourists to interrupt the experience (very much unlike the museum in Hiroshima).