Grayscale Postcard of the Smithsonian Institution Castle, February 13, 1905, Smithsonian Archives - History Div, Grayscale postcard of the Smithsonian Institution Building, or Castle. The front has a white border. The postcard is addressed to Leo. R. Laybourn in St. Paul, Minnesota. The card is postmarked in February 1905 in Washington and arrived in St. Paul on February 13, 1905..