A group of Chinese archaeologists found a ‘terror bunker’ from World War IIwhere Japanese researchers conducted hair-raising experiments on humans and collected data.

The site _located in northeast China, near the city of Anda in Heilongjiang Province_, was used by Unit 731 of the Imperial Japanese Armywho conducted some of the most brutal biological warfare experiments between 1935 and 1945, details The independent.

“Historical records show Unit 731 experiments at the Anda site included infect prisoners with deadly diseases and test new biological weapons”, reported South China Morning Mail. “Some of the scariest studies were done in underground bunkers designed to contain and control the spread of infection.”

Built in 1941, the Anda Special Test Range served as Unit 731’s largest, best-equipped, and most-used test facility, created by Japanese microbiologist Shiro Ishii in 1936.

The Germ Warfare Department, which oversaw it, conducted most of the experiments on humans in specialized prisons.

The heavily guarded test area was surrounded by a barbed wire fence. Above-ground facilities included an airstrip, warehouses, barracks, pits, and triangular metal frames used as bombing targets.

Laboratories, observation and dissection rooms, as well as guard cells were built underground to maintain secrecy and protect against air raids.

The underground facilities include barracks, garages, bathhouses, dining halls and wells, some connected by tunnels, he explains. South China Morning Mail.

The Anda site was destroyed in August 1945 by Unit 731 along with other facilities to erase evidence of their experiments.

“Most of the surface buildings were destroyed except for the airstrip.”, said archaeologists.

Former Division Commander Lin Kou of Unit 731, Sakaki Hayao, described an experiment “extremely cruel” made in the Anda Field just months before the Japanese surrendered in their testimony before the Shenyang Special Military Court in 1956.

Hayao said so saw people tied to wooden stakes and exposed to anthrax by bacteria-filled bombs dropped from airplanes or detonated at close range. “It was a particularly brutal act.”

After Japan’s surrender, the US granted immunity to the secret unit leaders and denied any knowledge of their gruesome experiments on POWs and civilians, including men, women, children, and even infants.

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These are known to include the dissection of living subjects, tests for frostbite and syphilis, as well as exposing victims to fatal diseases. Unit researchers developed ways to weaponize bubonic plague, anthrax, cholera and typhoid.

About 3,000 people are believed to have been used as test subjects.