The Pentagon (Wikipedia
9 Things You May Not Know About the Pentagon -- History
On January 15, 1943, work was completed on the new headquarters for the U.S. War Department (the modern-day Department of Defense) in Arlington, Virginia. The massive complex, commonly known as the Pentagon, was built to house the nearly 30,000 defense workers tasked with helping America win World War II. With more than 17 miles of corridors, it remains one of the largest office buildings in the world, and has become a symbol—for better and for worse—of military might. Eighty years after its completion, here are nine things you may not know about the Pentagon.
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Editor: Wikipedia's entry on the Pentagon is very comprehensive. That link is here.