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The Pentagon: America’s Command Center

Picture the largest office building in the world. Are you seeing a massive skyscraper towering over Shanghai or New York or Singapore? If so, clearly, you didn’t look at the title of this video, because it’s five stories high, found in Arlington, Virginia, and has five sides. It is, of course, the Pentagon. 

It’s hard to think of a single thing that defines the Pentagon. Its one-of-a-kind shape has brought it attention since before it was built, yet, it’s so much more than that. It was one of the sites of the world’s deadliest terrorist attack. It houses the most powerful government agencies in the world. And it was built really fast. Clearly, there’s a lot to learn about the Pentagon besides what meets the eye. Let’s get started.


Before World War Two, the US Department of Defense didn’t exist, and neither did a handful of the US military’s current branches. There was no Joint Chiefs of Staff. No Air Force. But there was a Department of War, founded in the late 18th-century when America was still the world’s youngest country. 

When we look at modern America, we see a military superpower focused on asserting its dominance over the world, but that was not always the case. The United States before World War One was isolationist, so, when they found themselves getting roped into the Great War, they expanded the headquarters of the Department of War. The DoW moved into the Navy and Munitions building, along Constitution Avenue on the National Mall in Washington DC. However, this was meant to be a temporary move, as the Great War forced the DoW to expand far beyond this building’s capacity. 

Henry L. Stimson, former Secretary
of War and State.

In the late 1930s, a new War Department Building was built in the Foggy Bottom neighborhood of DC, but, again, this one could not contain the entire DoW. Instead, it was quickly handed over to the State Department to become their headquarters. When World War Two broke out in Europe, America responded by expanding their DoW even more, despite initial claims that they had no desire to get entangled in this growing conflict. 

Henry Stimson, the Secretary of War, found the current lack of space unacceptable, and, in collaboration with congressman Clifton Woodrum from Virginia, organized a congressional hearing in July of 1941. The proposal for a new building was approved, on the condition that the new building was a long-term solution to the lack of space that had plagued the DoW for the last several decades. In other words, it needed to be gigantic.


Despite the requirement that the new building house the entire DoW, the US government placed a few restrictions on the building’s material and structure. First of all, it could only incorporate minimal amounts of steel, as President Roosevelt and the War Department wanted to leave as much as possible to use for ammunition and weapons for the upcoming war. The second requirement was that the building would be limited to four stories tall, meaning it would need a massive footprint to accommodate all the people who would work there.

The Potomac River in Washington, D.C.
The Potomac River in Washington, D.C. by Billy Hathorn is licensed under CC-BY-SA

This huge footprint immediately disqualified any areas actually inside the District of Columbia, given the area’s high concentration of buildings. Instead, planners selected a site across the POTOMAC RIVER in Virginia, a massive pentagonal space called Arlington Farms. As such, the architecture team designed an irregular pentagon-shaped building to fit the land. FDR then determined that the location in Arlington Farms would obstruct the view of the capitol from Arlington Cemetary, the historic military graveyard, disqualifying the spot from consideration.

Instead, Roosevelt selected a site where the small Hoover Airport stood, an area that wouldn’t obstruct any views to or from the city. The land was larger, allowing for more freedom of shape and layout, but it was too late for an entire redesign. So, the architects kept the pentagonal shape but made it an equilateral instead of irregular. The higher-ups from the DoW liked this shape, as it was reminiscent of old 18th and 19th-century fortifications.

Congress authorized funding for the new building in July of ’41, and President Roosevelt approved the site on September 2nd. The government owned much of the land for the site, but an additional 297 acres (1.16 sq km) were purchased for $2.2 million (equivalent to $29.9 million in 2019). This brought the total area for the project to almost 600 acres (2.43 sq km). Eventually, about 300 acres were dedicated to other projects, leaving about 290 for the Pentagon. The building itself would only stand on a fraction of that land, but this included area for new roads and landscape projects that would make the building more accessible to the incredible number of employees who would eventually work there.


On September 11th of 1941, the entire project contracts, totaling $31,100,000 (equivalent to $423 million in 2019), were finalized with a handful of private companies. Ground broke on the new construction site on the very same day, marking the beginning of one of the most impressive construction projects in history. The already urgent project became even more so in December of 1941, as the Pearl Harbor attack encouraged General Brehon Somervell to request 1,000,000 square feet (93,000 sq m) of space available by April 1943.

Complete initial drawings weren’t provided until a month after construction began. For nine months of the project, construction was ahead of the design and architecture, leading to discrepancies in the materials used and those suggested. To cut down on steel use, the majority of the building was built with reinforced concrete. 680,000 tons of sand were drawn from the Potomac River bank to make the concrete, resulting in a man-made lagoon near the River Entrance that persists today. Another way development was sped up was by eliminating all elevators from the plans, instead preferring concrete ramps.

The proximity to the Potomac helped in the procurement of sand for the concrete, but it also caused problems. Elevations varied across the building site from 10 to 40 feet (3.0–12.2 m) above sea level, and much of the land lacked ideal soil conditions for a strong foundation. Two retaining walls had to be built to resolve the uneven ground, and cast-in-place piles dealt with the soil conditions.

The building was constructed one wing at a time so that DoW employees could move in and begin working while construction continued on another part of the building. The compartmentalized process allowed for the project’s progressive acceleration, as the building team completed each wing faster than the previous one. By January 15th, 1943, almost three months before the date that General Somervell requested 1,000,000 square feet of office space, construction on the entire project was complete, giving the DoW 3,700,000 sq ft (340,000 sq m) of office and 6,600,000 sq ft (610,000 sq m) in total. 

The project took all of 16 months to complete. Again, the building, which, at the time of completion, was the largest building in the world (by floor area), was completed in just 16 months in the 1940s, all while the country was gearing up for the most massive, industrialized war that mankind has ever seen. The project’s total cost was $83 million (equivalent to $1.13 billion in 2019). The man who led the entire development project, Colonel Leslie Groves, an Army Corps of Engineers Officer, was immediately assigned to direct the Manhattan Project.


The Pentagon spans 28.7 acres (116,000 square meters) and includes an additional 5.1 acres (21,000 square meters) for the central courtyard. While that acreage is less than 10 percent of what was initially assigned to the project, the rest of the land was used to update the surrounding area’s road system. The building has five sides, five floors above ground, two basement levels, and five ring corridors per floor with a total of 17.5 mi (28.2 km) of hallway.

As previously stated, the Pentagon is the world’s largest office building, covering 6,600,000 sq ft (610,000 sq m). That’s more than 1,000,000 square feet larger than the second-largest office building in the world. The building is large enough to fit five copies of the US Capitol building within its footprint, with space for three full-sized football pitches in the center courtyard. The building is so large and receives so much mail that it’s made up of six different postal codes, one for each sub-office of the Department of Defense.

While the building’s shape was initially determined by the form of Arlington Farms, it quickly became apparent that it would benefit staff working in the Pentagon. It could take 15-20 minutes to walk from one end to the other in a rectangular building of the same volume and floor space. But in the Pentagon, the continuous shape and central courtyard mean that no two points in the building are further than seven minutes apart.

Not only is it easy to move around within, but it’s also straightforward to get to. Upon its opening in 1943, many employees took buses or taxis to work each day. To accommodate this, a two-story bus and cab station connects to the building. Though bus travel is less common for employees today, at its height, the station allowed for the flow of 30,000 people per hour in and out of the Pentagon.

Once inside, the building essentially contains anything you may need for your daily life, earning it the nickname “The Secret City.” The building houses a drug store, laundromat, shoe store, Best Buy, hospital, doctor’s clinics, restaurants, conference center, library, and athletic center. They also have a police force and fire fighting unit dedicated entirely to the building.

If you ever get the chance to walk through, you may notice that each bathroom set is mirrored by a second set right beside each other. This may seem like a convenient way to ease traffic while waiting for a toilet, but it actually has a much more sinister history. When the Pentagon was first built in the 1940s, the majority of Southern states still enforced segregation. Given its location in Virginia, the building included a set of “Whites Only” bathrooms and a set for everyone else. President Roosevelt toured the facility before its official opening and saw the “Whites Only” sign above one bathroom door. This infuriated the President, who demanded that the signs be taken down and segregation laws ignored. The two sets of bathrooms remain, but they are used by all and remain a sobering reminder of the world that existed when the building was first built. 


The Pentagon is more than just a symbolic building full of history and Best Buys. It’s also the workplace for 26,000 Americans. The large majority, around 23,000, are employed by the military, while the rest are civilian employees. 

The Department of War, the agency that the building was built for, was abolished in 1947 to make way for the Department of Defense, which inherited the building from the old department. Nowadays, the Department of Defense encompasses almost every aspect of American national and, let’s be honest, global defense, and the Secretary of Defense stands above all of it. 

The Office of the Secretary of Defense includes 30 sub-offices, including well-known agencies like the National Security Agency (NSA), the one that probably spies on your text messages, and many more agencies that you’ve never heard of. The Departments of the Army, Navy, and Air Force also fall beneath the DoD umbrella, encompassing the four branches of the military, as the Marine Corps is a sub-branch of the Navy. The fifth and final major office is the Joint Chiefs of Staff. These offices are based within the Pentagon, allowing for the utmost collaboration between branches and agencies. However, we can’t guarantee that the Army and Navy officers actually get along with each other.

The nature of the work requires that the vast majority of what goes on within the Pentagon walls remains Top Secret. Conversations regarding Top Secret information are technically forbidden within the walls of the Pentagon, though. However, one area where sensitive information can be verbally shared is in the handful of Sensitive Compartmented Information Facilities, commonly known as Skiffs. These skiff’s incorporate materials that are meant to defeat any electronic form of eavesdropping, so that information can be shared without the fear of anyone listening in from miles away. The Situation Room is the most famous skiff, but the Pentagon is believed to contain more than any other building in the world.


On September 11th, 2001, exactly 60 years since construction began on the DoD headquarters, a Boeing 757 was hijacked by terrorists from al-Qaeda and crashed into the side of the Pentagon. Obviously, the most horrific and notorious scenes from the day were at the World Trade Center complex in New York. While the Twin Towers were a primary target for their economic significance, the Pentagon was chosen because of its role as the nation’s military command center.

The plane broke through 3 of the 5 corridors and caused the partial collapse of one of the wings. 184 people were killed, including those on the airplane. However, while the tragedy of the lives lost cannot be understated, a handful of miraculous circumstances ended up saving hundreds, if not thousands of lives.

The airliner was flown by hijackers directly into the western-facing wall of the Pentagon. The hijackers may not have realized that the Pentagon was undergoing renovations at that time, so just 800 of 4,500 regular workers were in that portion of the building that day. The majority of the completed upgrades focused on safety from attacks just like this one.

It was the only portion of the building with a sprinkler system, and a web of steel columns and bars were built into the structure to withstand bomb blasts. The web connected to other parts of the building that weren’t directly hit by the airplane, providing up to 30 additional minutes before the damaged portion collapsed and saving the lives of hundreds of people who were able to crawl out of the burning building during that time. The west wing also had blast-proof windows, each one two-inches thick and weighing 2,500 lbs (1,134 kg), which stayed intact despite the crash and the fire. 

The local fire department’s response was swift and emphatic, but they were aided by the tenants of the building. Keep in mind, these are not typical office employees. These were men and women working for the US military, so they viewed this attack as a call to action. Many of the firefighters who were there that day spoke of how different the victims of this attack were from those of typical large fires. Instead of fleeing the scene looking for safety, the men and women of the Pentagon wanted to run back into the fire to save their compatriots. Some moved to the building’s undamaged areas to complete their work for the day, seeing their jobs as too essential to be postponed by a terrorist attack. 

It took 48 hours for firefighters to get the blaze under control, but, on September 12th, with the fire still raging on, every operational office in the building was filled with working employees. 

Exactly 7 years after the terrorist attack, a memorial was dedicated to the lives lost in the Pentagon that day. The memorial includes a 2-acre park with 184 benches, each dedicated to a different victim.


Renovations had been underway for several years when the 9/11 attacks occurred, but, of course, the priority immediately became the reconstruction of the wing that was destroyed. The rebuilding was referred to as Project Phoenix, and the construction team showed similar dedication as those who originally built the Pentagon, completing the reconstruction well ahead of schedule. 

Following the completion of Project Phoenix, the construction team continued renovations throughout the rest of the building, increasing security features even more than initially planned. The entire building is fitted with shatterproof glass, sprinklers, and steel webbing for structural support. But building more robust defenses into the structure is only relevant if an attack on the Pentagon is successful. Though the details are intentionally unclear, Pentagon officials claim that any similar attack would not succeed this time around. The building is surrounded by anti-aircraft missiles and other defense systems that inspire confidence that the facility will not be targeted again.

Not all renovations are focused on defense, though. For one, the building now contains seventeen elevators, indeed a welcome sight for employees tired of climbing five floors by stairs every day. The building has been upgraded for sustainability and modern communication technology, including 100,000 miles of telephone cables. The latest renovation project took 17 years to complete and should carry the historic Pentagon to its Centennial birthday in 2043. 

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