|By David B. Gleason from Chicago, IL - The Pentagon, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4891272|
2. Build for the Pentagon began on Sept. 11, 1941 and was completed less than two years later, on January 15, 1943. With the supply shortages associated with World War II, steel was in high demand, so it is primarily made from concrete – 435,000 tons of it. Due to this, architects designed the building as short instead of tall. Enough steel was saved to build a battleship.
3. There are 17.5 miles of corridors housed within the Pentagon’s walls.
4. The original U.S. military complex was planned to be in Washington DC’s Foggy Bottom neighborhood. However, once built, the new building was quickly deemed to be too small to house the department and DoD (then called the War Department) was split across 17 buildings. The original building later was given as a home to the U.S. State Department.
7. There are 131 stairways, 13 elevators and 19 escalators in the complex.
8. Physically, the Pentagon is located on the Virginia side of the Potomac River in Arlington County, however, each department has a Washington D.C. mailing address – there are six zip codes in the Pentagon – 20301 (Secretary of Defense), 20318 (Joint Chiefs of Staff), 20310 (United States Army), 20330 (United States Air Force), 20350 (United States Navy) and 20380 (United States Marine Corps). A whopping 1,200,000 pieces of mail are sent and received monthly.
9. Did you know you can move between any two points in the Pentagon in about 10 minutes? This was designed intentionally to make things more efficient, but it seems the building’s vast size wasn’t in that thought process. Story has it at least a couple of high-ranking officials have gotten lost from time to time trying to find their way to or from their offices. The building is truly that big.