Students prepare to present flowers to martyrs during an exhibition on the Tokyo Trial at the Museum of the War of Chinese People's Resistance Against Japanese Aggression in Beijing, capital of China, Dec. 13, 2019. In front of the crowd in black, China's national flag flew at half-mast as the nation held a memorial ceremony Friday to mourn the 300,000 victims of the Nanjing Massacre. (Xinhua/Peng Ziyang)