Pentagon, The


The Pentagon, located in Arlington, Virginia, is home to the Department of Defense and serves as military headquarters for the United States. The enormous, 6.24-million-square-foot concrete structure is the largest office building in the world, covering thirty-four acres. Built to house the burgeoning War Department on the eve of the United States’ entry into World War II (1939–1945), the headquarters was constructed in just seventeen months. From the moment Secretary of War Henry L. Stimson and Army Chief of Staff General George C. Marshall moved into the building in November 1942, the Pentagon has served as the focal point of American military planning and operations. Vital decisions regarding the D-Day invasion of Europe and the development of the atomic bomb were made at the Pentagon during World War II. In subsequent years the Pentagon has been the setting for many more critical decisions, from the Cold War and the Vietnam War (1961–1975) to the wars in Iraq and Afghanistan. On September 11, 2001, terrorists flew a hijacked passenger jet into the Pentagon, killing 184 people and seriously damaging the building but not shutting it down. With its iconic, five-sided shape, the Pentagon is one of the world’s most recognizable buildings and it has come to serve as a symbol of American military strength.


In 1941 the War Department, racing to prepare for possible war with Germany and Japan, faced a dire space problem. The department was growing at an exponential rate, but had run out of room for its 24,000 workers, who were scattered in seventeen buildings across Washington, D.C. The department had been evicted from the ornate State, War, and Navy Building (now known as the Eisenhower Executive Office Building) in downtown Washington because the White House needed additional space. The War Department set up headquarters in the Munitions Building on the National Mall, but it was not adequate. A new building constructed in the Foggy Bottom neighborhood (now home to the State Department) was deemed to be too small.

In July 1941, Brehon Burke Somervell, chief of army construction who would later head logistics operations during World War II, summoned his staff to a meeting and announced that the army would build a new headquarters. The building Somervell wanted to create was too big to fit in Washington, D.C., and would have to be built on the other side of the Potomac River in Arlington. He wanted a headquarters with four million square feet of office space—twice as much as the Empire State Building—that was big enough to hold 40,000 people, with parking for 10,000 cars. Despite the capacity, the building could be no more than four stories high because a tall building would obstruct views of Washington and require too much steel that was then urgently needed for battleships and weapons.

The site Somervell had in mind was at the foot of Memorial Bridge, on ground that is now part of Arlington National Cemetery. The odd-shaped plot, bound on five sides by roads, a railroad, and a line of trees, guided the designers. On July 20, the architects presented Somervell with plans for a five-sided building that fit the shape of the land. As the plans moved quickly and with approval up the chain of command to United States president Franklin D. Roosevelt, Somervell prepared to break ground on the site.

But once the proposal was made public, a storm of protest erupted over the plan to build such a large building on the prominent ground below the Lee Mansion, a location that would ruin the famed vista overlooking the Memorial Bridge and Lincoln Memorial. Late in August, Roosevelt, over Somervell’s strenuous protests, ordered the site moved a mile downriver to a location known as Hell’s Bottom. The low-lying ground included brickyards, old whisky stills, industrial sites and a portion of Washington-Hoover Airfield, the city’s old airport. Land needed for the road network that would accompany the building included Queen City, a neighborhood that was home to about 300 African American families. Although the new site was not pentagonal, the designers, led by California architect George Edwin Bergstrom, had already concluded that a five-sided shape made an efficient design for moving large numbers of people and utilities through the building. And given Somervell’s demands for speedy completion, there was no time to change the design.

To construct the building, Somervell chose John McShain, a Philadelphia builder who was making a name constructing other landmarks in the area, including the Jefferson Memorial and National Airport. Overseeing the construction for the army was Somervell’s hard-charging deputy, Colonel Leslie R. Groves, who would later gain fame as head of the Manhattan Project to construct an atomic bomb.

Construction and World War II

Ground was broken for the new headquarters on September 11, 1941. Architects had time to complete only preliminary plans, and the designers were moving barely one step ahead of the pile drivers. Despite a lack of finished plans, the work moved quickly. The pace accelerated after the Japanese attack on Pearl Harbor on December 7, 1941, as the dire need for a central army headquarters became clear. By March, the construction workforce had grown to more than 13,000 and included workers from around the country who descended on the big job site looking for work during the tail end of the Great Depression.

Though the building was less than half completed and workers were still driving piles, the first employees moved into the Pentagon on April 30, 1942, at Somervell’s insistence. These first employees, who had to enter the building by balancing on pieces of lumber atop puddles of mud, dubbed themselves “the plankwalkers.” They coped with clouds of dust, miserable heat, and incredible noise. Somervell, seeking more space for war workers, made a last-minute decision to build a fifth floor, one of several additions that brought the office space to more than six million square feet.

The headquarters was officially known as the New War Department Building in Arlington, but the officers and workers involved in constructing the building had already nicknamed it the “pentagonal building.” In May 1942, the War Department changed the name to the Pentagon Building, and, a year later, to simply the Pentagon.

Work on the building was completed by mid-February 1943. The finished structure had seventeen cumulative miles of labyrinthine corridors that spread through five floors and five rings that circumnavigated the building. The Pentagon included an enormous concourse with shops for employees. In the middle was a muddy five-acre pentagonal courtyard planted with a few scrubby trees. Over time, as the trees and grass grew, the courtyard would become a favored spot for lunch and Pentagon gatherings. The building population would reach as many as 35,000 during the war, but has fluctuated considerably over the years, numbering between 20,000 and 25,000 at the start of the twenty-first century.

As the war drew to a close, debate grew on what function the Pentagon would serve in peacetime. Roosevelt, even before the building’s construction, favored converting the building into an archive for government records. Others suggested a hospital for veterans. The army, however, was quite content to hold onto the big building.


In 1947 the Pentagon became home to the newly created National Military Establishment (which preceded the Department of Defense) and almost all military services. The first secretary of defense, James Forrestal, moved into the building on September 22, 1947. Headquarters was established for the newly created air force, and the navy, which had balked at coming into the Pentagon during the war, was ordered to move in. Only the U.S. Marine Corps held out, maintaining its headquarters in a nearby building until 1996.

In the 1950s, as Cold War tensions grew, the Pentagon became the focal point for command and control of America’s nuclear fleet. Secretary of Defense Robert McNamara established the National Military Command Center in 1962, just weeks before the high-stakes nuclear standoff between the United States and the Soviet Union during the Cuban Missile Crisis severely tested the Pentagon’s command capabilities.

As the Vietnam War escalated during the 1960s, the Pentagon became a target of antiwar protests. The largest and most famous was the October 21, 1967, march on the Pentagon. Some 35,000 protesters, among them prominent antiwar activists such as Abbie Hoffman, author Norman Mailer, and Dr. Benjamin Spock, marched from the Lincoln Memorial to the Pentagon. Some of the protesters scuffled with military police in occasionally violent confrontations that continued long into the night but did not result in any fatalities. On May 19, 1972, a bomb placed by the terrorist group the Weather Underground exploded in a fourth-floor bathroom. No one was injured, though the bomb caused $75,000 damage. In the decades that followed, the Pentagon was a frequent target of antinuclear demonstrators who threw paint or animal blood on the steps and columns of the building. On December 20, 1983, rising concerns over the threat of terrorism led to the closure of a bus tunnel that had been used to drop passengers beneath the concourse since the building opened.

These years of turmoil and the general wear and tear that the building had experienced over its first fifty years, along with needs for extensive upgrades to technical infrastructure, necessitated a building-wide renovation and overhaul. Based on its distinctive design and the fact that it was the setting for many historic moments, the Pentagon was designated a National Historic Landmark on October 5, 1992. Deteriorating conditions within the Pentagon, including leaking pipes, crumbling concrete, and ancient wiring, aggravated by decades of neglected maintenance, forced the U.S. Congress to approve a long-delayed renovation that began in 1994. The ceiling-to-slab renovation plan divided the Pentagon into five wedges, each in turn to be stripped down to bare concrete floors and columns and refitted with up-to-date wiring, lighting, furniture, and communications infrastructure. The work also included construction of a remote delivery facility to accept mail and goods for the Pentagon, lessening the dangers presented by truck bombs. By September 2001, workers had completed renovations on the first of the wedges.

September 11, 2001

On September 11, 2001, the Pentagon, along with the World Trade Center in New York City, was attacked by the al Qaeda terrorist network, led by fugitive Saudi billionaire Osama bin Laden. Five hijackers, acting under a plan masterminded by al Qaeda operative Khalid Sheikh Mohammed, seized American Airlines Flight 77, which had departed Dulles International Airport at 8:20 that morning en route to Los Angeles. At 9:37 a.m. the Boeing 757 was flown into the first floor of the Pentagon’s west wall at a speed of approximately 460 knots. All of the plane’s fifty-eight passengers and crew, as well as the hijackers, died instantly.

Wreckage and fuel cascaded through three rings of the building, decimating the Navy Command Center, the Defense Intelligence Agency’s comptroller office, and army budget offices. The death toll of 125 inside the building would have been much greater but for a series of happenstances. The plane struck the only portion of the Pentagon that had been renovated and was thus equipped with blast-resistant windows, structural improvements, and sprinkler systems. Most significantly, the ongoing renovations meant the area was only half populated, further reducing casualties.

The reconstruction, assigned to the Pentagon Renovation Program under the leadership of Lee Evey, was christened the Phoenix Project and became a race to repair the 400,000 square feet of damaged space in the building as quickly as possible. Workers, fired with patriotic resolve, pledged to restore the building within one year of the attack, working around the clock and through holidays to get the job done. By the first anniversary of the attack, all offices at the point of impact were restored and occupied by employees.

Plans for a memorial to the victims began soon after the attack. A panel of judges, which included representatives from the families of victims, considered hundreds of proposals submitted via a blind competition. They chose a proposal to cover the two-acre site along the plane’s path to the building with trees and 184 benches built atop small reflecting pools, each representing a victim. Ground was broken for the Pentagon Memorial on June 15, 2006. The memorial was dedicated on September 11, 2008, the seventh anniversary of the attack, before an audience of almost 20,000, including hundreds of victims’ family members, survivors, and rescuers.

By the summer of 2009, the renovation of the Pentagon was more than three-quarters finished and slated for completion in 2011.

July 1941
Brehon Burke Somervell, chief of army construction, summons his staff to a meeting and announces that the army will build a new headquarters to enhance military communication and efficacy.
July 21, 1941
Architects present Brehon Burke Somervell, chief of army construction, with plans for the new army headquarters: a five-sided building that fits the shape of the area designated for construction.
August 20, 1941
After public protest erupts over the plan to build a large War Department building on the prominent ground below the Lee Mansion, President Franklin D. Roosevelt orders the site moved a mile downriver to a location known as Hell's Bottom.
September 11, 1941
Ground is broken for the new War Department headquarters—what will later be named the Pentagon.
April 30, 1942
The first employees move into the as-yet unfinished Pentagon.
May 1942
The War Department changes the name of the New War Department Building to the Pentagon Building, and, a year later, to simply the Pentagon.
February 1943
The construction of the Pentagon Building is completed.
The Pentagon becomes home to the newly created National Military Establishment (later called the Department of Defense) and most military services.
Secretary of Defense Robert McNamara establishes the National Military Command Center in the Pentagon.
October 21, 1967
Thirty-five thousand protesters against the war in Vietnam, among them activists such as Abbie Hoffman, author Norman Mailer, and Dr. Benjamin Spock, march on the Pentagon, which results in a few violent confrontations with military police.
May 19, 1972
A bomb placed by the terrorist group the Weather Underground explodes in one of the Pentagon's fourth-floor bathrooms. No one is injured, but the bomb causes $75,000 damage.
December 20, 1983
Concerns over the threat of terrorism lead to the closure of a bus tunnel that had been used to drop passengers beneath the concourse since the Pentagon opened.
October 5, 1992
The Pentagon is designated a National Historic Landmark.
Deteriorating conditions within the Pentagon aggravated by decades of neglected maintenance force a long-delayed building-wide renovation.
September 2001
Renovations are completed on the first of the Pentagon's five wedges slated for upgrading and improvement.
September 11, 2001, 8:20 a.m.
American Airlines Flight 77 departs Dulles International Airport en route to Los Angeles.
September 11, 2001, 9:37 a.m.
After being seized by five hijackers, American Airlines Flight 77 is flown into the first floor of the Pentagon's west wall at a speed of approximately 460 knots.
June 15, 2006
Ground is broken for the Pentagon Memorial dedicated to the victims and events of September 11, 2001.
September 11, 2008
The Pentagon Memorial is dedicated.
  • Brauer, Carl M. The Man Who Built Washington: A Life of John McShain. Wilmington, Delaware: Hagley Museum and Library, 1996.
  • Brinkley, David. Washington Goes to War. New York: Ballantine Books, 1989.
  • Creed, Patrick and Rick Newman. Firefight: Inside the Battle to Save the Pentagon on 9/11. New York: Random House, 2008.
  • Fine, Lenore and Jesse A. Remington. The Corps of Engineers: Construction in the United States. Washington, D.C.: Office of the Chief of Military History, U.S. Army, 1972.
  • Goldberg, Alfred. The Pentagon: The First Fifty Years. Washington, D.C.: Historical Office, Office of the Secretary of Defense, 1992.
  • Goldberg, Alfred, Sarandis Papadopoulos, Diane T. Putney, Nancy K. Berlage, and Rebecca Hancock Welch. Pentagon 9/11. Washington, D.C.: Department of Defense, 2007.
  • Vogel, Steve. The Pentagon: A History—The Untold Story of the Wartime Race to Build the Pentagon and to Restore it Sixty Years Later. New York: Random House, 2007.
APA Citation:
Vogel, Steve. Pentagon, The. (2020, December 07). In Encyclopedia Virginia. https://encyclopediavirginia.org/entries/pentagon-the.
MLA Citation:
Vogel, Steve. "Pentagon, The" Encyclopedia Virginia. Virginia Humanities, (07 Dec. 2020). Web. 19 Jul. 2024
Last updated: 2020, December 07
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