Eighty years ago this week, the U.S. dropped an atomic bomb on Hiroshima, Japan on Aug. 6, 1945. Three days later, another fell on the city of Nagasaki. Between 120,000 and 220,000 people died in the blasts or from burns, other wounds and radiation exposure over the next few months.

Following are some facts about the bombing of the Japanese city of Hiroshima and a second attack on Nagasaki three days later -- the only times nuclear weapons have been used in war. Japan surrendered on Aug. 15, 1945, ending its role in World War Two.

Against the backdrop of rising Russia-US tensions, Japan held a ceremony on Wednesday morning commemorating 80 years since the United States' atomic bombing of Hiroshima. Speakers warned the representatives of 120 countries and regions in attendance that escalating threats of nuclear warfare "blatantly disregard" the horrifying legacy of the 1945 attacks that killed over 240,