Washington DC: The Smithsonian "Castle"
"I then bequeath the whole of my property, . . . to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase & diffusion of knowledge among men."
With this one sentence in his will, an Englishman who had never visited the United States, started a process that has grown to a virtual empire of museums, research centers, and other establishments with holdings of 154 million items.
The "Castle", the Smithsonian's first building (1849-1855,) is still its headquarters today. Located at a prominent spot on the National Mall, the structure's proper name is the Smithsonian Institution Building, but most everyone refers to it as "the Castle." The crenelated tops of two of its towers make this moniker quite apt.
The architect for the Castle was James Renwick, who would later go on to design St. Patrick's Cathedral in New York City and the Renwick Gallery (originally the Corcoran Gallery of Art) in D.C., among many other distinguished buildings. Renwick's overall design here was neo-gothic, but much of the detailing is Romanesque Revival. For example, all of the windows as well as the archivolts of the porte cochère (seen here at the center of this photo) are Romanesque. This style makes the building stand out from its neighbors, which are all Beaux Arts, Second Empire, modern, or postmodern.
Another feature that marks the castle as distinct is its use of Seneca red sandstone on the exterior. The design originally called for white marble or yellow sandstone, but Mr. Renwick and the building committee saved the taxpayers quite a few bucks by deciding on the cheaper and easier-to-work material from Seneca quarry, not too far up the C&O Canal in Montgomery County, MD.
Going back to Mr. Smithson, the wealthy English scientist left his estate to his nephew, with the stipulation that should said nephew die without heirs, the fortune would then be donated to the United States, per the opening sentence of this post. Happily for us, the nephew never married and when he died, we got the money for establishing the Smithsonian.