Secret Cities

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On December 21, 1938, German scientists Otto Hahn and Fritz Strassmann became the first people to successfully split, or fission, a uranium atom.

This groundbreaking experiment sent shockwaves throughout the scientific community.

It quickly led to concerns among the U.S. and European allies that Nazi Germany might be on the verge of creating atomic weaponry.

In response to this looming threat, Albert Einstein, prompted by colleagues, sent a cautionary letter to President Franklin Roosevelt on August 2, 1939,

suggesting that the Nazis could be in the process of creating a formidable new weapon unlike any other.

Roosevelt quickly set up the Advisory Committee on Uranium, and then, in 1941, several British scientists persuaded Roosevelt to embark on an atomic weapons program in the U.S.,

hoping to beat Nazi Germany in the race to develop this new technology.

As the world experiences Christopher Nolan's new film, Oppenheimer, it's taking a new look at the development of this great and terrible weapon under the organization of the Manhattan Project.

I'm Jason Epperson, and today on America's National Parks, we're taking a look at the sites that would be chosen to develop a bomb that would undoubtedly change the world.

America's secret cities.

The Manhattan Project was delayed due to a slew of setbacks.

It was only on September 1942 when the project took flight after General Leslie R. Groves of the U.S. Army was appointed as the project's manager.

Groves ensured adequate funding, mobilized a skilled and diverse workforce, including leading scientists, and selected three prime locations for the project.

Each site was meticulously chosen, considering the project's unique requirements for success.

On September 9, 1942, two days after being assigned the lead role, General Groves approved an idyllic location in East Tennessee.

A series of valleys and rolling hills approximately 20 miles west of Knoxville, with the Appalachian Mountains to the east and the Cumberland Plateau to the west.

This sparsely populated area proved to be an ideal choice to develop what would eventually become Oak Ridge.

At the time of the selection, Oak Ridge was named the Kingston Demolition Range, and later the Clinton Engineer Works.

Oak Ridge was slated to hold four production plants, gaseous diffusion, pile, centrifuge, and electromagnetic.

Prior to choosing the site, General Groves' team scouted several locations throughout the U.S.

California was also scouted, but was too close to the coast and therefore too vulnerable to potential enemy attack.

Lastly, several sites in Washington State were considered, but too much work was required to install power lines for the immense energy needed.

And like California, it was considered too vulnerable.

East Tennessee fit the bill perfectly. The ridges and valleys allowed for natural separation of the proposed plants.

The sparse population meant that in the event of a catastrophe, any potential loss of life would be low.

Enough inland to prevent a potential enemy attack.

In addition, the various nearby hydroelectric dams operated by the Tennessee Valley Authority ensured that the site could be efficiently powered.

Lastly, displacement of residents was deemed to be more manageable than in a more urban location.

The immediate area only had about 1,000 families at the time.

During the fall of 1942, land acquisition began with the purchase of over 55,000 acres at a cost of about $3.5 million in 1942 dollars.

By spring of 1943, the site was officially designated Clinton Engineer Works, and the fall of that year, construction had begun on a massive building for enriching uranium.

The need for construction workers at this new gaseous diffusion plant named K-25 and other uranium enrichment facilities in the city

caused the population of Oak Ridge to increase from 13,000 people as originally planned to over 75,000 by the end of the war.

At its peak, K-25 employed 12,000 workers and was one of the linchpins of what would become the most populous Manhattan Project site in the country.

While Oak Ridge was developed by Groves and his team to enrich uranium, a site had also been found to produce plutonium.

With Knoxville, Tennessee being so close to Oak Ridge, Groves ruled out the addition of a plutonium production nuclear reactor in the region.

A potential failure of a reactor could have dire consequences for the population of the nearby city.

Once again, Groves turned to Washington State as an option.

Any potential plutonium production site required three things, water, power, and a large area with few people.

The Pacific Northwest met the criteria.

The large and fast-moving Columbia River could provide water for cooling the reactors,

and the Grand Coulee Dam could provide the hydroelectric power needed.

The lightly populated open expanse of southeastern Washington could provide the space to ensure safe and efficient operation.

In January of 1943, after having personally visited the site, General Groves acquired 780 square miles of land along the Columbia

at a cost of $5.1 million in 1943 money.

With sufficient dams and power lines, the Hanford Engineer Works began construction,

so named because of a tiny village of less than 100 residents located within the plot of land.

The Manhattan Project now had an ideal location for plutonium production.

By October, construction of Hanford's B Reactor had begun.

By 1944, the Clinton Engineer Works in East Tennessee and the Hanford Engineer Works in Washington State

were well on their way to producing enriched uranium and plutonium, respectively.

And by that time, on an isolated mesa in New Mexico, world-renowned scientists,

led by J. Robert Oppenheimer, were hard at work developing designs for the atomic bombs.

The search for a site to house the weapons design and research facilities took a few twists and turns

before settling on the isolated mesa top.

Groves' subordinate, Major John H. Dudley, was tasked with finding a remote location west of the Mississippi River

that was a minimum of 200 miles from an international border

and had ample outdoor space for testing and room for 265 residents.

Dudley initially proposed Oak City, Utah, a small desert community that fit the requirements.

However, this site would demand the removal of a large swath of productive farmland as well as several families.

Dudley set his sights further south.

Along with Oppenheimer, Dudley next scouted a narrow canyon about 40 miles north of Santa Fe.

Oppenheimer objected to the confines of a canyon and proposed to Dudley a location on a mesa above the canyon

that was home to the Los Alamos Ranch School, a boarding school for boys operated by Ashley Pond.

This proved to be an ideal spot.

Isolated with ample space for housing, research and testing, it also had a panoramic view that Oppenheimer desired.

Ashley Pond was willing to sell.

On November 25, 1942, the War Department approved the purchase of the Los Alamos Ranch School for $440,000.

At 5.30 a.m. Mountain Wartime on July 16, 1945,

after lengthy development, the world's first atomic test device, codenamed Trinity,

exploded in New Mexico's Tularosa Basin, ushering in the Atomic Age.

Established in 2015, the Manhattan Project National Historical Park preserves and interprets the nationally significant historic sites,

stories, and legacies associated with the top-secret race to develop atomic weapons during World War II.

On August 6 and 9, 1945, the U.S. dropped atomic bombs on Hiroshima and Nagasaki, Japan.

Imperial Japan announced their surrender on August 15 and formally signed on September 2, bringing World War II to a close.

Although the three sites chosen for the Manhattan Project were quite different in terms of geography, population, and purpose,

successful development of the world's first atomic weapons could not have been achieved without all three working together.

The Manhattan Project quickly grew from its New York-Manhattan District headquarters to more than 30 top-secret sites around the country.

This episode of America's National Parks was written with help from the National Park Service and hosted by me, Jason Epperson.

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