At the corner of Xi'an Avenue and Qingnian Road in Changchun, half of a two-story building stands as a physical scar from 1932. This green-brick structure, topped with a sharp gabled roof shaped like the character for 'human,' once housed the Kwantung Army Fifth Army Hospital. In 1936, under new Japanese military hospital regulations, the facility expanded its role from basic treatment to medical testing. Behind these brick walls, military doctors conducted biological experiments, vivisections, and bacterial infections on human subjects, operating in coordination with Unit 731.

The architecture itself reveals this dark transition. The protruding front entrance once echoed with the heavy boots of Japanese military staff. Inside, the air carried the sharp scent of carbolic acid, masking the suffering of prisoners held for biological testing. In 1948, after the liberation of Changchun, the People's Liberation Army Air Force took over the site, converting it into a military hospital. Decades later, during the Reform and Opening-up era, the building opened to the public, operating first as the Blue Sky Hospital and later as the Aerospace Hospital.

In 2011, demolition crews removed one wing of the main building when the Aerospace Hospital relocated. In 2009, the city designated the site as a municipal cultural relics protection unit. In October 2024, local officials inspected the surviving structure to plan its preservation. Today, the remaining green bricks and the truncated gabled roof stand in silence, bearing witness to the grim realities of wartime occupation.