In 1937, when Japan invaded China, Dr Karl Gunther was in the process of commissioning Jiangnan Cement Factory in Nanjing (formerly Nanking). The factory had been equipped with German made machinery.

Hundreds of thousands of Chinese attempted to flee Nanjing upon the Japanese invasion. Dr Gunther opened the gates of the cement factory and allowed, reportedly, 40,000 to 50,000 Chinese nationals to enter.

A year earlier, Germany and Japan had signed an anti-communism pact and became, of a sort, allies. Indeed, in 1938, Germany officially recognized Japan's claim to Manchuria.

Anyway, Dr Gunther put German flags at the front gates of the cement factory and declared it to be German territory. He refused requests from the Japanese army to enter the factory and the Japanese army refrained from doing so forcefully for fear of antagonizing Germany.

Thus, Dr Gunther is said to have been personally responsible for saving the lives of 10s of thousands of Chinese nationals.

Additionally, Dr Gunther was able to freely move around Nanjing during the Japanese occupation and he apparently accumulated a large collection of photographs of the atrocities committed by the Japanese army.

Dr Gunther returned to Germany in 1950 and he passed away in 1987.