For most of its existence, the sphere remained hidden enclosed under a large wood and metal cube.
But the timber has now disintegrated away revealing this extraordinary contraption with a sinister past.
Fort Detrick was the center of the US biological weapons program from 1943 to 1969.
Human volunteers could also breath in metered aerosols of infectious organisms through these ports.
Such test allowed scientists to determine the lethal doses of biological agents.
Scientists also tested the most effective method of dissemination of deadly agents, from bombs to sprays.
These personnel worked in the area surrounding the sphere without benefit of or need for respiratory protection.
Photo:usarmywhitecoat.com
The Eight Ball wasnt always used for offensive purposes.
The sphere was also used in the development of vaccines against other nations biological weapons.
Workers standing outside the 1-million-liter sphere, circa 1968.
Because of its historical scientific significance, the Test Sphere is now on the National Register of Historic Places.
