For most travelers, Hiroshima can be divided up into two main sites. Inside the town itself, the major destination is Peace Park, the restored site of the first nuclear bomb explosion during warfare, now dedicated to world peace and the abolishing of nuclear weapons.
The bomb was dropped on August 6, 1945, exploding at an altitude of about 1800 feet which virtually destroyed the city in an instant. The most notable feature within the park is the skeletal remains of a large building that survived the initial impact a few hundred feet away from ground zero.
The park itself is beautiful (and entirely wifi free), however the history behind it and corresponding museum puts a somber mood on the entire area. The second site requires a quick day trip outside of Hiroshima city to Miyajima island, and brings about a much higher spirit.