A paper flower is seen on the wall remembering the victims at the Memorial Hall of the Victims in Nanjing Massacre by Japanese Invaders in Nanjing, capital of east China's Jiangsu Province, April 4, 2017. A mourning ceremony was held here by survivors and family members of victims in the Nanjing Massacre during Tomb-Sweeping Day, or Qingming, when Chinese people commemorate their deceased loved ones by visiting tombs. (Xinhua/Han Yuqing)