This is a description of the Pentagon, the headquarters of the United States Department of Defense, located in Washington D.C. The building is an iconic symbol of the American military and is the world's largest office building. It is a five-sided structure with five concentric rings, and
From Wikipedia
The Pentagon is the headquarters of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C. The building was constructed on an accelerated schedule during World War II. As a symbol of the U.S. military, the phrase The Pentagon is often used as a metonym for the Department of Defense and its leadership.