A bunker once used for experiments on humans by Japanese scientists has been partially unearthed in China, according to a report from LiveScience.
Dubbed the “horror bunker,” it was used by the infamous Unit 731 of Japan’s Imperial Army from 1941 until 1945 when Japan surrendered in World War II. While the exact location had previously been unknown, archeologists from the Heilongjiang Provincial Institute of Cultural Relics and Archaeology now believe it sits in the city of Anda, in northeast China.
The archeologists who made the discovery said it “highlights the ongoing legacy of Unit 731’s atrocities and their impact on global efforts to prevent biological warfare.”
The bunker is U-shaped and measures 108 feet long and 67 feet wide with tunnels and interconnected rooms, according to LiveScience. It’s believed to have labs, barracks, and observation and dissection rooms, though the researchers have not yet entered the facility, the outlet notes. Researchers used drilling, excavation, and geophysical prospecting to discover the facility. According to The Independent, a circular room in the bunker may have been used as an observation site after the human subjects were infected with chemical agents or diseases.
Unit 731 was formed in 1937 with the objective of promoting public health, according to the Atomic Heritage Foundation, but it would soon begin terrifying experiments on humans against their will. Some of these experiments reportedly include being injected with diseased animal blood, organ and limb removal, and testing of chemical weapons, grenades, and bacterial bombs. Researchers said the bunkers were used to prevent the spread of pathogens being tested.
One Unit 731 veteran told The New York Times in 1995 that he “saw samples” containing internal organs, feet, and heads at the detachment’s headquarters — a separate location — “with labels saying ‘American,’ ‘English’ and ‘Frenchman,’ but most were Chinese, Koreans and Mongolians.”
“Those labeled as American were just body parts, like hands or feet, and some were sent in by other military units.”
Though the experiments constituted clear war crimes, Shiro Ishii, the leader of Unit 731, escaped prosecution by the United States in exchange for the details of the results of the experiments. LiveScience notes that this information was sent to Fort Detrick in Maryland, which once housed the American biological weapons program. He was able to continue performing medicine in Japan following the war, according to The Independent.
While it’s not clear exactly how many people were subject to experimentation, a report from Montana State University estimates that the unit killed between 3,000 and 12,000 people.