Hiroshima, city in Japan, south-western Honshu, capital of Hiroshima Prefecture at the head of Hiroshima Bay. The city was founded in 1594 on six islands in the Ota River delta. Hiroshima grew rapidly as a commercial city, and after 1868 it was developed as a military base. On August 6, 1945, during World War II, the first atomic bomb was dropped on the city. The Supreme Allied Headquarters reported that 129,558 people were killed, injured, or missing and a further 176,987 made homeless by the bombing. (In 1940 the population of Hiroshima had been 343,698.) The blast flattened more than 10 sq km (4 sq mi), about 60 per cent of the city. Every August 6 since 1947, thousands participate in multidenominational services in the Peace Memorial Park built on the site where the bomb exploded. In 1949 the Japanese dedicated Hiroshima as an international shrine of peace.