The EM origin story begins with Robert Oppenheimer and the birth of the Manhattan Project. It was a project that forever changed the course of history and ultimately led to the world’s largest environmental cleanup program. But how solid is your knowledge of the Manhattan Project? Let's find out!

The Manhattan Project was made up of three primary sites, Hanford, Washington, Oak Ridge, Tennessee, and Los Alamos, New Mexico. The quiz below is designed to test your historical knowledge of the three "secret cities" and set the stage for learning more about the ongoing environmental cleanup mission being executed as a result of the nation's nuclear weapons production and testing.

Choose a quiz category in the green bar below.

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The Secret Cities - Then & Now

Hanford Then

For the Manhattan Project, the Hanford Engineer Works produced plutonium at a roughly 600-square-mile (965-square-km) site along the Columbia River in Washington state. The Hanford Site was selected because of an abundant supply of cold Columbia River water needed to cool nuclear reactors, ample available hydroelectric power, mild climate, excellent transportation facilities, and distance from major population centers. Workers at the Hanford Site constructed and operated the world’s first nuclear production reactors that produced the plutonium used in the Trinity Test and in the atomic bomb dropped on Nagasaki, Japan, on August 9, 1945.

Producing Plutonium

Starting in 1943, the United States engineered and built the world’s first full-scale production nuclear reactor in Hanford, Washington along with two additional production reactors, uranium fuel fabrication facilities, and chemical separation facilities. As in the ancient dream of alchemists of turning lead into gold, the Hanford process transmuted one element, uranium, into another, plutonium. Approximately 4,000 pounds (1,814.36 kg) of uranium are needed to produce 1 pound (0.45 kg) of plutonium. Eventually, enough plutonium was produced to be used in the first successful test of a nuclear device at Trinity Site and in the Fat Man plutonium bomb dropped over Nagasaki, Japan, on August 9, 1945. Read the articles below to learn more about the plutonium production process and the places critical to its development. 

Hanford Now

The Hanford Site is responsible for the safe and environmentally acceptable cleanup of the site, including groundwater remediation; hazardous waste and facilities decontamination and disposal operations; treatment and disposal of radioactive chemical liquid waste; and the design, construction and commissioning of the world’s largest complex of nuclear vitrification facilities, the Waste Treatment and Immobilization Plant.

Calendar Year 2023 Accomplishments 

  • Continued tank waste treatment through Tank Side Cesium Removal operations, with more than 800,000 gallons of waste treated.
  • Completed heat up of the first tank-waste vitrification melter in the Waste Treatment Plant, producing its first container of test glass in October.
  • Completed more than 40 upgrades to the Effluent Treatment Facility, boosting its capacity and efficiency to support DFLAW operations.
  • Completed the Integrated Disposal Facility where vitrified waste from the Direct-feed Low Activity Waste facility will be taken for disposal.
  • Treated more than 2 billion gallons of contaminated groundwater for the ninth consecutive year.
  • Completed a 144,000 square-foot interim surface barrier over the U Tank Farm to protect groundwater.
  • Completed demolition of the K West Reactor Annex.
  • Continued upgrades at the Waste Encapsulation Storage Facility to prepare to transfer 1,936 radioactive capsules to dry-storage casks.
Employees sit and stand around computers

RICHLAND, Wash. – Hanford Site crews recently made project history when they started pouring the first molten glass from a 300-ton melter into a stainless steel container at the Waste Treatment and Immobilization Plant. There is no waste or chemical simulants in the glass used to test the melter and associated equipment at the plant’s Low-Activity Waste Facility. Workers monitored the pour from a control room as a stream of glass was released from the melter, as seen in this short video.

Los Alamos Then

In Los Alamos, New Mexico, Manhattan Project administrators found an ideal location for the secret laboratory where they designed and built the world’s first atomic weapons. During the Manhattan Project, Los Alamos became the home to many of the top scientific minds of the day: J. Robert Oppenheimer, Norris Bradbury, Richard Feynman, Hans Bethe and many more luminaries. These scientists worked together to develop the theoretical and experimental tests that created the first atomic weapons, using enriched uranium from Oak Ridge and plutonium from Hanford. Today, the nucleus of this once-secret city is still Los Alamos National Laboratory. Explore the people, places, and stories of Los Alamos to learn more about this once secret community.

Los Alamos Now

The EM Los Alamos Field Office (EM-LA) is dedicated to the cleanup of legacy contamination of radioactive and chemical materials and waste resulting from operations during the Manhattan Project and Cold War eras at the Los Alamos National Laboratory in New Mexico. EM-LA’s cleanup scope includes legacy waste remediation and disposition, soil and groundwater remediation, and deactivation and decommissioning of excess buildings and facilities.

Calendar Year 2023 Accomplishments 

  • Commenced abatement and hazard removal activities at Building 251, a high-risk excess facility.
  • Initiated the Building 280 demolition project.
  • Commenced the LS412 slab and soil removal project.
A bulldozer removing debris in a large dirt field
Cleanup of the Middle DP Road Site in Los Alamos included removal of more than 5,917 cubic yards of waste and debris for disposal.

Oak Ridge Then

The rolling hills and narrow valleys of East Tennessee proved to be the ideal location for the top-secret atomic weapons program developed here beginning in 1942. Oak Ridge, Tennessee was home to several massive Manhattan Project facilities employing thousands of workers during and after World War II and was the headquarters for the project after relocating from New York City. These facilities in Oak Ridge operated with one goal in mind: enriching uranium for use in the world’s first atomic bombs. 

Enriching Uranium

The three massive Manhattan Project facilities at Oak Ridge— the Y-12 Electromagnetic Isotope Separation Plant, the K-25 Gaseous Diffusion Plant, and the S-50 Liquid Thermal Diffusion Plant—operated for one purpose: to enrich uranium for use in an atomic bomb. These three facilities separated the rare uranium-235 isotope from the more common uranium-238 isotope, each using a different mass separation method. 

Though the three facilities began construction and went into operation at different points during World War II, they were designed to operate simultaneously, with uranium hexaflouride and uranium tetrachloride passing from S-50 to K-25 and finally Y-12, each stage raising the concentration of U-235. Y-12 began operating in the fall of 1943, using calutrons to separate the uranium isotopes. S-50 went online in late fall of 1944. 

By the spring of 1945, sections of the K-25 plant began using the more efficient gaseous diffusion method. When all plants were in operation, the uranium would be slightly enriched at S-50, further enriched at K-25 and final enrichment at Y-12. The enriched uranium was transported to Los Alamos and used as fuel for Little Boy, the atomic bomb dropped on Hiroshima, Japan, August 6, 1945. 

Oak Ridge Now

The Oak Ridge Office of Environmental Management (OREM) is the landlord of East Tennessee Technology Park (ETTP), and it is also responsible for the Comprehensive Environmental Response, Compensation, and Liability Act cleanup at Y-12 and the Oak Ridge National Lab. OREM has achieved significant risk reduction across the Oak Ridge Reservation, including the removal of all facilities at ETTP. With demolition complete at ETTP, OREM transitioned the skilled, experienced workforce from there to address the many high-risk facilities at Oak Ridge National Laboratory and Y-12. Demolition prep and deactivation work is underway at numerous buildings at those sites. OREM’s work will address DOE’s largest inventory of high-risk, excess contaminated facilities (former research reactors, isotope production facilities, and former process buildings); eliminate the site’s remaining inventory of uranium-233; remediate areas with dense mercury contamination; and provide valuable real estate for the National Nuclear Security Administration and the Office of Science missions.

Calendar Year 2023 Accomplishments 

  • Completed demolition of the Low Intensity Test Reactor.
  • Began early site preparation for the Environmental Management Disposal Facility. 
  • Released two draft Records of Decision about groundwater for public comment.
  • Broke ground on the K-25 Viewing Platform at ETTP.
  • Forged new partnerships to aid workforce development.
Group photo with shovels and dirt for groundbreaking event.

Officials with the National Nuclear Security Administration and Consolidated Nuclear Security, the Y-12 National Security Complex management and operations contractor, break ground for the new Lithium Processing Facility.

Explore Additional Resources

Documentary Series

In early September 2023, the National Security Research Center (NSRC) announced the online release of the three-part documentary “Oppenheimer: Science, Mission, Legacy.” The film, produced by the NSRC and based on rare photos, documents, and footage from its unclassified legacy collections, highlights the impetus for the Manhattan Project’s creation and Los Alamos National Laboratory’s continuing mission. Episode 1 is featured below. To see all three episodes click here


Several episodes of LANL podcasts feature information about Oppenheimer:

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J. Robert Oppenheimer: Science (Part 1)
Los Alamos National Lab

National Security Research Center Resources 

The National Security Research Center (NSRC) is the classified library at Los Alamos National Laboratory. The NSRC traces its lineage to the technical library formed by J. Robert Oppenheimer in 1943 as part of the Manhattan Project. They are part of the Lab's fascinating history. Today, the NSRC is one of the largest scientific / technical libraries in the federal government with collections that number in the tens of millions. It also houses unclassified collections, including photos, related to the people, events, and scientific achievements that make up our nation's nuclear history. Click here to visit the NSRC page and find videos, articles, photos and podcasts focused on the Manhattan Project. 

Photo with notebook paper and writing on the left and a black and white photo of a person on the right.

Los Alamos National Laboratory recently digitized a collection of more than 10,000 cards containing the personnel information of Manhattan Project staff, including famous scientists, such as J. Robert Oppenheimer, Richard Feynman, Emilio Segrè and Edward Teller.

National Security Science - The Oppenheimer Issue

This issue of National Security Science magazine explores the dynamic legacy of physicist J. Robert Oppenheimer, who came to Los Alamos New Mexico in 1943 to direct the top-secret weapons laboratory of the Manhattan Project. In just 27 months, as the world would later learn, he led the effort to create the atomic bomb, helping end World War II.

National Security Science art director Brenda Fleming created this issue’s cover art using digital oil paints and watercolor brushes. “I’ve seen hundreds of black and white photos of Oppenheimer,” she says. “I hoped a color portrait would not only capture Oppie’s piercing blue eyes but also convey how alive his legacy is today.” Los Alamos National Laboratory

One Park, Three Sites, Countless Stories

The Manhattan Project National Historical Park has a visitor center in the three main communities of the Manhattan Project: Hanford, Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee. All three communities are designated as American World War II Heritage Cities to honor the contributions of these communities and their citizens who stepped into the workforce to support America's war effort during World War II. Start exploring their incredible Manhattan Project resources here.  

The Life & Legacy of Robert Oppenheimer

Learn more about his life and legacy through a series of articles, profiles, virtual tours of his Los Alamos home, and filming locations featured in the 2023 Oppenheimer Hollywood biopic.

Plan Your Visit

These are not your traditional parks where you drive through an entrance gate into the park. Instead, you drive into the communities where you can explore the park visitor centers, historic sites, museums, points of interest and so much more. The Manhattan Project parks works with community partners to provide a variety of places that collectively share the story of the Manhattan Project. Start planning your visit!

Photo showing three different buildings.
The Manhattan Project National Historical Park has a visitor center in the three main communities of the Manhattan Project: Hanford, Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee.

Department of Energy Manhattan Project Resources

The Department of Energy (DOE) has an extensive catalog of Manhattan Project historical resources to help you learn even more about this pivotal period. Click the link below to explore a two-part podcast series that covers the dropping of the first atomic bomb and how DOE is preserving that legacy.

The link also includes an extensive photo gallery, additional information on preservation work and an incredible “Women of the Manhattan Project” historical timeline. Continue learning here.

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Manhattan Project Podcast - Part 1
Department of Energy