Sixty years ago, on August 6, 1945, at 8:15 AM Japanese time, an American B-29 bomber, the Enola Gay, the dropped an atomic bomb over the city of Hiroshima. The blast killed approximately 80,000 people and injured 35,000. Another 60,000 died as a result of fallout by the end of the year.
U.S. President Harry S. Truman, discouraged by the Japanese response to the Potsdam Conference's demand for unconditional surrender, made the decision to use the atom bomb to end the war in order to prevent what he predicted would be a much greater loss of life were the United States to invade the Japanese mainland. On August 5, "Little Boy" (the nickname for one of two atom bombs available for use against Japan) was loaded onto Lt. Col. Paul W. Tibbets' plane on Tinian Island in the Marianas. Tibbets' B-29, named the Enola Gay after his mother, left the island at 2:45 a.m. on August 6. Five and a half hours later, "Little Boy" was dropped, exploding 1,900 feet over a hospital and unleashing the equivalent of 12,500 tons of TNT.
There were 90,000 buildings in Hiroshima before the bomb was dropped; only 28,000 remained after the bombing. Of the city's 200 doctors before the explosion; only 20 were left alive or capable of working. There were 1,780 nurses before-only 150 remained who were able to tend to the sick and dying.
The City of Hiroshima mainatins an English webpage here, with a lot of links about their history and their Peace Memorial Ceremony held every year on August 6th.
Reference: This Day in History, August 6