BEIJING, Aug. 6 (Xinhuanet) -- The western Japanese city of Hiroshima marked the 60th anniversary of its 1945 atomic bombing Saturday, with the mayor urging the United Nations to establish a committee to try to realize and maintain a nuclear weapon-free world.

    Dignitaries including Japanese Prime Minister Junichiro Koizumi attended the ceremony.

    The following are some key facts about the atomic bombings of Hiroshima and Nagasaki, the world's first and only nuclear attack so far.

    Hiroshima, some 690 km southwest of Tokyo, is the capital city of Hiroshima prefecture. It lies in the southwestern coast of Japan's biggest island. After the middle of the 19th century, it gradually became an army base.

    Nagasaki is the capital city of Nagasaki prefecture. It lies on the western tip of the southern Japanese island of Kyushu. The Japanese government opened a seaport there in the 16th century at the request of the Portuguese. From the early 17th century to the middle of the 19th century, Nagasaki was the only seaport for foreign trade in Japan.

    After Italy and Germany surrendered to the anti-fascist allied powers during World War II, Japan chose to continue its desperate struggle.

    On July 26, 1945, the United States, Britain and China reached the Potsdam Declaration, demanding that Japan surrender immediately and unconditionally. But Japan turned a deaf ear to it.

    At 8:15 a.m. on Aug. 6, 1945, a US B-29 bomber called "Enola Gay" dropped a 4,000-kg uranium-235 bomb on Hiroshima, killing 78,150 people instantly and leveling all buildings in the city.

    The bomb, nicknamed "Little Boy," exploded about 580 meters above the center of the city, setting off a surge of heat reaching4,000 Celsius degrees across a radius of about 4.5 km.

    At 11:02 a.m. on Aug. 9, the United States dropped a 4,900-kg plutonium-239 bomb, nicknamed "Fat Man," on Nagasaki.

    It exploded about 503 meters above the ground, instantly killing about 100,000 of the city's estimated population of around230,000. A total of 60-70 percent constructions in the city were destroyed.

    Emperor Hirohito surrendered on Aug. 15, marking the end of the second World War.

    So far, the atomic bombing of Hiroshima and its afte reffects have killed an estimated 240,000 people. Over 135,000 people were killed in Nagasaki. Enditem