In the summer of 1941, War Department affairs were being conducted in 23 buildings in and around the city. To his annoyance and embarrassment, Secretary of War Henry Stimson discovered that the recently completed New War Department Building had proved inadequate. A new and bigger office building was needed – yesterday. On July 17, 1941, Brig. Gen. Brehon Somervell, the recently installed head of the Army’s Construction Division, seized the opportunity with both hands. Turning to his chief of design, Lt. Col. Hugh “Pat” Casey, he said, “Pat, we’re going to build a new War Department Building.”

“George, I’m speechless. This is the most fantastic operation I have ever witnessed. It’s unbelievable.”

– Gen. George C. MarshallBritish Field Marshal Sir John Dill to on viewing construction of the Pentagon

It would be built in Virginia, because there was no room in Washington, D.C. for the size of building Somervell wanted: a headquarters containing four million square feet of office space (almost double that of the Empire State Building) capable of holding 40,000 people and supplying parking spaces for 10,000 cars; estimated cost $35 million. He then said, “We want 500,000 square feet ready in six months, and the whole thing ready in a year.” He issued orders to have initial plans on his desk at 9 o’clock Monday morning.

The submitted design conformed to the shape of the proposed site bordering Arlington National Cemetery, a pentagon. Refined designs retained that shape after aesthetic objections were raised and it was moved. Eventually its shape also became its official name: the Pentagon.

Ground was broken on Sept. 11, 1941, and the first employees moved into it on April 30, 1942. Originally four floors, a fifth floor was added when the building was half completed. Col. Leslie Groves, who would later head the Manhattan Project, was made the project’s chief of operations, and he drove the upwards of 15,000 people working on the Pentagon relentlessly. By the time it was completed in February 1943, the building covered 29 acres, had 17.5 miles of corridors and had cost more than $83 million.

During construction it was referred to as “Somervell’s Folly.” After it was occupied, other names superseded it, including “Five-Sided Wailing Wall,” “Five-Sided Funny Farm,” and many unprintable ones. Because of the rapid pace of construction, accidents were endemic and a handful of workers were killed, though tales of them buried beneath poured concrete are apocryphal.

During construction it was referred to as “Somervell’s Folly.” After it was occupied, other names superseded it, including “Five-Sided Wailing Wall,” “Five-Sided Funny Farm,” and many unprintable ones.

The nightmarish production schedule necessitated the construction of special apartments for overnight stays within the Pentagon’s rising walls by supervisors, such as project executive officer Capt. Robert Furman. A few months after the Pentagon’s completion, Furman, now a major, encountered now Brig. Gen. Leslie Groves at Arlington’s Army Navy Country Club. Recalling Furman’s intelligence and calm demeanor, Groves offered Furman, who was between assignments, a job of a highly classified nature. Furman reported to Groves’ office the following day, was sworn into the Manhattan Project, and became responsible for discovering everything possible about the Nazi’s atomic bomb. His work took him all over Europe and behind enemy lines.

When in Washington, he couldn’t resist availing himself of the best perk available in the Pentagon, one known only to him. On a trip back, he noted that the apartment he had used during construction had not been dismantled. Located in the middle of the Ordnance Department’s office bay, the windowless apartment contained a bedroom and bathroom with a shower. As he “was the only one left” who knew the room’s purpose and still had keys to it, from that point on whenever Furman was in Washington, he stayed there. When he emerged from the place in the middle of the morning carrying his suitcase, he got many an odd look from the clerical staff. “They all wondered what was in that room,” he said. Eventually building administrators discovered Furman’s “grandfathered” abode, confiscated his keys, and demolished it.

To this day people get lost in its maze. Even big shots prove susceptible to the building’s labyrinth configuration. In 1989, shortly after he became secretary of defense, Dick Cheney became lost in one of the Pentagon’s basements and wandered around for 10 minutes before finding his way out.