Catch the Hikari bullet train to Hiroshima from Kyoto. It takes about 2 hours including a change at Shin Osaka or Shin Kobe.
Spend a few hours in the Hiroshima Peace Memorial Museum, which documents the atomic bombing of Hiroshima in 1945. Today will be a tough one, the stories of human suffering and some of the photographs in the museum are very upsetting, but it's very important for everyone to visit and understand why that nuclear war can never happen.
Other things to see around the Peace Memorial Park are the Hiroshima National Peace Memorial Hall for the Atomic Bomb Victims, the haunting remains of the A-Bomb Dome, now a UNESCO World Heritage Site which stood only 160m away from the hypocenter of the bomb blast, the Peace Flame, which will only be extinguished once all nuclear weapons have been destroyed, the Memorial Cenotaph, the Children's Peace Monument with its beautiful collection of brightly coloured paper cranes, the Atomic Bomb Memorial Mound containing the cremated ashes of 70,000 unidentified victims of the bomb, the Memorial Tower to the Mobilized Students. There are even some trees in the park still deeply scarred by the heat of the bomb blast.
Before you leave the park, ring the Peace Bell with a prayer for world peace. Its beautiful world map on the surface has no border lines, and is meant to symbolise a unified world.
After a sobering and emotional day, it is time to celebrate the rebirth of the city and the current residents and raise a glass over dinner to world peace. The city's signature dish is Okonomiyaki, a savoury pancake made of pork, cabbage, seafood, eggs, green onion and topped with fish flakes and a sweet savoury sauce. It's astonishingly good. A great place to try this is at Okonomiyaki-mura, a building with 24 small restaurants all specialising in the dish. Sit round the metal teppan griddle and watch your meal be cooked in front of you! You then eat it with a small metal spatula and chop sticks.