Soviet President Mikhail Gorbachev’s resignation 30 years ago was a momentous event that ended an era by drawing a line under the USSR’s existence. The Moscow photo chief for The Associated Press was the only foreign photographer who caught the terminal moment of the Soviet Union. On Dec. 25, 1991. Liu Heung Shing decided that an image of Gorbachev putting down the speech he had just delivered live on TV to announce stepping down would best capture the watershed event. Liu chose a slow shutter speed to show the president’s paper in motion and to convey the fleeting historic moment. The photograph made the front pages of many newspapers around the world.