It looks a little like a prison or a reminder of a horror movie.
A long, deserted, and dimly-lit corridor.
To date, there are only three United States Mint buildings. One in Philadelphia, another in Denver, and the "new" Mint in San Francisco.
On this day, the Old Mint was open to the public and I heard eventually turned into a museum. The 2nd photo was actually a vault where the gold or coins were stored, but today like all the other vaults in the corridor, stand empty.