A Washington D.C. resident frequently walks his dog past U.S. Government offices at night. He became curious as to why the lights were always on, even during weekends, in the basement of one particular building. There appeared to be frantic activity, with many trucks coming & going at all hours. All other government buildings in the area were obviously closed.
One recent evening, curiosity got the best of him. He walked around the block to the front of the building. Before him stood the ediface of The U.S. Treasury Printing Office.