The term 'Big Brass Container' can be solved by the 8-letter word 'Pentagon'. The Pentagon is a large building located in Arlington, Virginia, and is the headquarters of the United States Department of Defense. It is one of the world's largest office buildings, with about 6, 500, 000 square feet of space. The building is shaped like a pentagon and is made of reinforced concrete and steel. It is surrounded by a large courtyard and five sides, each of which is lined with a wall of windows.