Tour Hiroshima Castle, a National Treasure. You can get a full view of the city of Hiroshima from the observation room in the highest floor of the castle. At the experience corner, getting into samurai wear and taking the commemorative photo is popular.
Stroll through the Daimyo Teien of the Edo Era. Admire the garden which is beautiful throughout all four seasons and then take a break enjoying matcha tea or coffee. The Hiroshima Prefectural Art Museum is next to the garden, so if you have time, drop by there as well.