The hook
The city rebuilt from the world's first atomic bombing, where a skeletal ruined dome is kept exactly as the blast left it, paired with a nearby island whose great vermilion shrine gate appears to float at high tide.
01Why it's worth it
On one day Hiroshima holds two of Japan's most powerful sights, and the contrast is the point. The Peace Memorial Park marks where an atomic bomb killed tens of thousands in an instant in 1945; the preserved shell of the A-Bomb Dome, left standing amid the destruction, and the unflinching museum make it one of the most sobering and important places anyone can visit, and the modern city that grew back around it is a quiet argument for peace. A short train and ferry away lies Miyajima, the shrine island, where the great red torii gate of Itsukushima stands out in the sea and seems to float when the tide is in, with tame deer, forested peaks, and old temples behind it. Grief and serenity in a single day, both handled with grace.
02How to experience it
Give the Peace Park and museum real time and quiet; this is remembrance, not sightseeing. Then take the ferry to Miyajima, timing it for high tide so the torii floats, and climb or ride up Mount Misen for the view. Eat the local okonomiyaki and oysters.