Trips Places Foods Stories Newsletters

Take your next trip with Atlas Obscura!

Our small-group adventures are inspired by our Atlas of the world's most fascinating places, the stories behind them, and the people who bring them to life.

Visit Adventures
Trips Highlight
Borneo orangutan
Malaysia • 12 days, 11 nights
Wild Borneo: Secrets of an Ancient Rainforest
from
Pastel de nata
Portugal • 8 days, 7 nights
Portugal: A Culinary Adventure from Porto to Lisbon
from
View all trips
Top Destinations
Latest Places
Most Popular Places Random Place Lists Itineraries
Add a Place
Download the App
Top Destinations
View All Destinations »

Countries

  • Australia
  • Canada
  • China
  • France
  • Germany
  • India
  • Italy
  • Japan

Cities

  • Amsterdam
  • Barcelona
  • Beijing
  • Berlin
  • Boston
  • Budapest
  • Chicago
  • London
  • Los Angeles
  • Mexico City
  • Montreal
  • Moscow
  • New Orleans
  • New York City
  • Paris
  • Philadelphia
  • Rome
  • San Francisco
  • Seattle
  • Stockholm
  • Tokyo
  • Toronto
  • Vienna
  • Washington, D.C.
Latest Places
View All Places »
The Ravne tunnels.
Ravne Tunnels
Colors and volumes in the patio.
Monterrey’s Contemporary Art Museum (MARCO)
Inside Wonderwerk Caves, underground caves and excavation, Kuruman, Northern Cape
Wonderwerk Cave
The ‘Old Secretariat’ government building in New Delhi.
The 'Old Secretariat'
Latest Places to Eat & Drink
View All Places to Eat »
The pavlova comes crowned with jewel-like fruit.
Central Park Boathouse
The Village Tavern of Long Grove - exterior.
The Village Tavern
Hunter House Hamburgers
L’Escamoteur
Names on the bartop.
The Dive
Recent Stories
All Stories Video Podcast
Most Recent Stories
View All Stories »
Burros Alfa and Beto, seen here with Luis Soriano in 2008, have been helping the teacher deliver books for more than 20 years.
How One Man and His ‘Biblioburro’ Spreads Literacy in Rural Colombia
Price Tower
What Happened to Price Tower, Frank Lloyd Wright’s Only Skyscraper?
Jeremy Bentham’s Auto-Icon in its new location in 2020
The Jeremy Bentham Auto-Icon: Why This Legendary Philosopher Put His Own Body on Display
The truth is out there—somewhere.
The Truth Is Out There at the Dreamland Resort (or Should We Say ‘Area 51?’)

No search results found for
“”

Make sure words are spelled correctly.

Try searching for a travel destination.

Places near me Random place

Popular Destinations

  • Paris
  • London
  • New York
  • Berlin
  • Rome
  • Los Angeles
Trips Places Foods Stories Newsletters
Sign In Join
Places near me Random place
All the United States Maryland Frederick One-Million-Liter Test Sphere

One-Million-Liter Test Sphere

This four-story steel sphere in Maryland was used to test biological weapons.

Frederick, Maryland

Added By
Tony Dunnell
Email
Been Here
Want to go
Added to list
CAPTION
One-Million-Liter Test Sphere in 2001.   U.S. Army
One-Million-Liter Test Sphere sometime before 1969.   U.S. Army
Workers at the test sphere at Fort Detrick.   Public Affairs Office, Fort Detrick, Maryland
The 8-Ball as seen on Google Maps.   Map Data ©2018 Google
A consent statement for one of the Operation Whitecoat experiments at Fort Detrick.   US Army
Been Here
Want to go
Added to list

About

The One-Million-Liter Test Sphere, aka “The 8-Ball,” is undeniably an impressive structure. It’s the largest biological warfare chamber and testing facility of its kind ever made, at least as far as we know. Still, there’s something sinister about this now nonoperational sphere in Fort Detrick, Maryland, in which explosive disseminators were once used to test pathogens against animals and human volunteers.

Back when it was operational, “The 8-Ball” looked like something the Red Skull would build in a cliff-top Nazi fortress before Captain America came in and smashed it all. Test Sphere 527, as it was also known, was a 40-foot-diameter steel sphere with a one-inch-thick carbon steel hull and a one-million-liter total volume. Total weight: 131 tons.

For most of its operational existence, which stretched from 1951 to 1969, it was enclosed within a 60-foot cube-shaped building sheathed in metal. The sphere itself was gas tight and climate controlled, and the entire complex routinely rated on a slight negative pressure so that any leaks would only allow clean air to enter, rather than allowing contaminated air to escape.

The point of all this was for the aerobiological study of “agents highly pathogenic to man and animals,” including nasty airborne biological weapons. "Hot" biological bombs were detonated inside the sphere, and the pathogen-filled munitions were tested in various ways.

Around the equator of the sphere were a series of access ports and test chambers. Some of these cabinets were for sample collection and for exposing small animal species, up to the size of a monkey, to the pathogens. Another access port was for the whole-body exposure of larger animals, including sheep and goats. A further four exposure cubicles were designed specifically for exposing human volunteers via masks.

The sphere was used most notoriously during the Operation Whitecoat study that began in 1954 (shortly before the start of the Vietnam War). This biodefense medical research program was carried out by the United States Army at Fort Detrick, using volunteers who were all conscientious objectors. These volunteers included many Seventh-day Adventists who wished to remain noncombatants but still help with the war effort.

The purpose of the research, they were told, was to help defend troops and civilians against biological attacks. Whether that was entirely true and no offensive capabilities were being tested is open to debate. But many vaccines that are used to protect against biowarfare agents and viruses were first tested on human volunteers during Operation Whitecoat. And despite years of volunteers being hooked up to “The 8-Ball” and breathing in infected air, none died, at least during the test period.

What happened to the majority of them after the tests is largely unknown. Of the 2,300 volunteers who took part in the various tests, the army has addresses for only 1,000. And of that 1,000, only 500 of the Whitecoats, as the volunteers became known, were ever surveyed after the tests had finished.

The test sphere was last used in 1969. In 1975, the building housing the sphere burned down, but the sphere was largely undamaged. Today, it sits nestled and exposed between buildings at Fort Detrick, a decontaminated and decommissioned relic of the Cold War. Due to its historic significance, it was placed on the National Register of Historic Places in 1977.

Related Tags

Weapons Science Military History Technology Forts Spheres Chemicals War Military

Community Contributors

Added By

Tony Dunnell

Edited By

abbymcgowan885

  • abbymcgowan885

Published

April 18, 2018

Edit this listing

Make an Edit
Add Photos
Sources
  • https://mht.maryland.gov/secure/medusa/PDF/NR_PDFs/NR-443.pdf
  • http://www.pbs.org/wnet/religionandethics/2003/10/24/october-24-2003-operation-whitecoat/15055/
  • https://www.fredericknewspost.com/news/politics_and_government/military/fort-detrick-s-eight-ball----a-relic/article_09a3c63c-fe2b-5950-8f76-79d2c14455b2.html
One-Million-Liter Test Sphere
Chandler St
Frederick, Maryland
United States
39.435279, -77.429101
Get Directions

Nearby Places

Carroll Creek Covered Bridge

Frederick, Maryland

miles away

Guess the Greyhound

Frederick, Maryland

miles away

National Museum of Civil War Medicine

Frederick, Maryland

miles away

Explore the Destination Guide

Photo of Frederick

Frederick

Maryland

Places 8

Nearby Places

Carroll Creek Covered Bridge

Frederick, Maryland

miles away

Guess the Greyhound

Frederick, Maryland

miles away

National Museum of Civil War Medicine

Frederick, Maryland

miles away

Explore the Destination Guide

Photo of Frederick

Frederick

Maryland

Places 8

Related Places

  • Walmer Castle

    Walmer, England

    Walmer Castle and Gardens

    This curious Tudor-era castle was once home to Napoleon's greatest adversary, the Duke of Wellington.

  • Signal Hill Tattoo performance.

    St. John's, Newfoundland and Labrador

    Signal Hill

    The first transatlantic wireless signal was received at this 17th-century fort.

  • Jacob Epstein’s “Torso in Metal from Rock Drill” sculpture at the Tate Britain.

    London, England

    Torso in Metal from Rock Drill

    This haunting sculpture was created as a statement on the mechanized warfare of the First World War.

  • Tilbury Fort drawbridges.

    Tilbury, England

    Tilbury Fort

    This star-shaped artillery fort protected the mouth of the Thames from the 16th century to the Second World War.

  • Fort Washington, Maryland

    Fort Foote Rodman Guns

    A mammoth pair of Civil War artillery guns abandoned out in the forest.

  • Old Power Plant of the Army Research Center in Peenemünde

    Peenemünde, Germany

    Peenemünde Army Research Center

    The NASA scientists behind Apollo 11 started out developing Nazi weapons at this abandoned German rocket factory.

  • Daugavpils, Latvia

    Daugavpils Shot Tower

    This Latvian shot factory is still used twice a year to manufacture bullets the old-fashioned way.

  • Baltimore’s Phoenix Shot Tower.

    Baltimore, Maryland

    Phoenix Shot Tower

    Once America's tallest structure, now a Baltimore landmark.

Aerial image of Vietnam, displaying the picturesque rice terraces, characterized by their layered, verdant fields.
Atlas Obscura Membership

Become an Atlas Obscura Member


Join our community of curious explorers.

Become a Member

Get Our Email Newsletter

Follow Us

Facebook YouTube TikTok Instagram Pinterest RSS Feed

Get the app

Download the App
Download on the Apple App Store Get it on Google Play
  • All Places
  • Latest Places
  • Most Popular
  • Places to Eat
  • Random
  • Nearby
  • Add a Place
  • Stories
  • Food & Drink
  • Itineraries
  • Lists
  • Video
  • Podcast
  • Newsletters
  • All Trips
  • Family Trip
  • Food & Drink
  • History & Culture
  • Wildlife & Nature
  • FAQ
  • Membership
  • Feedback & Ideas
  • Community Guidelines
  • Product Blog
  • Unique Gifts
  • Work With Us
  • About
  • FAQ
  • Advertise With Us
  • Advertising Guidelines
  • Privacy Policy
  • Cookie Policy
  • Terms of Use
Atlas Obscura

© 2025 Atlas Obscura. All Rights Reserved.