Visitors holding Chinese national flags have their photos taken in front of the 9.18 Historical Museum in Shenyang, Northeast China's Liaoning Province on Wednesday. Air raid sirens once again sounded through the city at 9:18 am on Wednesday. The "September 18 Incident" in 1931 was followed by Japan's full-scale invasion of China, triggering the 14-year-long war against Japanese aggression. Photo: IC