If you were to glimpse inside Building 20 at the Brooklyn Navy Yard (née the New York Naval Shipyard) some 150 years ago, you would have witnessed a spectacle of mechanical brawn and mind-boggling ingenuity unfolding within a machine shop that ranked as the most ultra-modern of its kind in the late 19th century. Completed at the end of the Civil War in 1865, the cavernous factory building was the facility where the Department of the Navy fabricated armor…
