Question : Why was the Pentagon built ?
I wanted to know why the U.S built one of the largest military office in the world so I went searching and I came across this website http://pentagontours.osd.mil/index.html and found out that in the summer of 1941 in Washington D.C that the work force was at 24,000 people (civilian and military) housed in 17 building so the government wanted to make some temporary buildings but one Brigadier General, Brehon B. Somervell dicided that they needed 583 acres of military center because of the world war that had broke out.
I hope I used a primary source.
React!