Activists shout slogans while holding China's flag as they gather outside the building that houses the Japanese embassy in Hong Kong on December 13, 2018, to mark 81 years since the 1937 Nanjing massacre. China says 300,000 people died in a six-week spree of killing, rape and destruction by the Japanese military that began in December 1937 after invading troops seized the city of Nanjing. Some respected foreign academics estimate a lower number of victims, but mainstream scholarship does not question that a massacre took place. / AFP / ANTHONY WALLACE   HONG KONG-CHINA-JAPAN-HISTORY-WWII-NANJING-WAR