About the ship and the city
The banner for USS Hiroshima is a combination of many cultural icons. It shows, at the center, the symbol of the Hiroshima prefecture, colored to resemble the national colors of Japan. The swords are the katana and wakizashi, which, together, make up a Samurai's daisho. The Starfleet commbadge identifies the ship as a commissioned Starfleet vessel and the Japanese characters identify the ship's namesake.

This plaque is located on USS Hiroshima's bridge.
The symbol of the Hiroshima prefecture identifies the region of Chugoku, on Honshu Island, which has Hiroshima city as its capital. The ship honors both the city and prefecture because she carries the name of both. The symbol is seen as the background for the site, as well as on Hiroshima's banner.
Hiroshima - Heiwa kinen Toshi (Peace Memorial City)
Hiroshima was founded in 1589, on the coast of the Seto Inland Sea, and became a major urban center during the Meiji period. The city is located on the broad, flat delta of the Ota River, which has 7 channel outlets dividing the city into six islands which project into Hiroshima Bay. The city is almost entirely flat and only slightly above sea level; to the northwest and northeast of the city, some hills rise to 700 feet.
During the First Sino-Japanese War (1894-1895), Hiroshima emerged as a major supply and logistics base for the Japanese military, a role that it continued to play during World War II. The city was heavily damaged in World War II by the nuclear weapon Little Boy, the second such device to be detonated, and the first ever used in military action. The American atomic attack on Hiroshima and Nagasaki was the major factor leading to the surrender of the Japanese Government several days later.
After the nuclear attack, Hiroshima was rebuilt as a "peace memorial city," and the closest surviving building to the location of the bomb's detonation was designated the Hiroshima Peace Memorial. The city government continues to advocate for the abolition of nuclear weapons, writing a letter of protest every time a nuclear weapon has been detonated anywhere in the world since the city's bombing, and has advocated more broadly for world peace.
Hiroshima gained city status on April 1, 1889 and was designated as a major city on April 1, 1980 by government ordinance.
Hiroshima was rebuilt after the war, with new modern buildings rising all over the city. In 1949, Hiroshima was proclaimed a City of Peace by the Japanese parliament, at the initiative of its mayor Shinzo Hamai (1905-1968). As a result, the city of Hiroshima was receiving more international attention as a desirable location for holding international conferences on peace as well as social issues. As part of that effort, the Hiroshima Interpreters' and Guide's Association (HIGA) was established in 1992 in order to facilitate translation services for conferences, and the Hiroshima Peace Institute was established in 1998 within the Hiroshima University.
Also, as a result of the atomic bombing, Hiroshima began to receive donations of streetcars from all over Japan. (After World War II, Japanese cities - like British ones - were anxious to get rid of their streetcar systems due to damage to the infrastructure, and so there were plenty of streetcars available to give away.) Hiroshima thus rebuilt its streetcar system along with the rest of the city, and thus Hiroshima is the only city in Japan with an extensive streetcar system (although other cities have streetcar lines). Some streetcars that survived the war - and the nuclear attack - were put back into service, and four of these are still running today. For the most part, however, Hiroshima has updated its streetcars over the years.

This image of Hiroshima Castle's keep is behind the desk in Hiroshima's Ready Room, as well as on the mess decks.

This image of Hiroshima's Peace Memorial sits in the Officer's mess.

This view of Hiroshima's Peace Memorial is in the Executive Officer's office.

This lovely image of the torii at Itsukushima shrine is on the Ready Room wall, as well.

Last, but not least, this oil of USS Hiroshima is found in the Commanding Officer's Ready Room and the Executive Officer's office.