The threat of a nuclear conflict between the United States and North Korea affected an event marking the anniversary of world’s second atomic attack. A crowd gathered in the Japanese city of Nagasaki Wednesday to remember the U.S. atomic bombing there in the final days of World War II. The attack took place on August 9, 1945. Three days earlier, U.S. forces had dropped an atomic bomb on the Japanese city of Hiroshima. The mayor of Nagasaki spoke at Wednesday’s observance. He said “A strong sense of anxiety is spreading across the globe that in the not too distant future these weapons could actually be used again.” He and the crowd observed a moment of silence at 11:02, local time -- the exact time when the atomic bomb was dropped. The ceremony took place a short time after U.S. and North Korea officials exchanged strong language about the North’s nuclear activities.