Named for British Scientist James Smithson, who died in 1829 and left most of his wealth to his nephew. The nephew (thankfully) left it to us with the stipulation it be named the Smithsonian Institution and be utilized by the United States "for the increase and diffusion of knowledge".
The Institution has evolved since its inception in 1846 to 19 museums, nine research centers and a zoo. Altogether, it has come to be called "the nation's attic" for good reason: it's eclectic holdings number 138 million, making the Smithsonian the largest museum in the world.
Additional Smithsonian facilities are located in 5 other states (as well as Panama), and 168 other museums have qualified as affiliates.
This shot is of the original museum a/k/a "The castle", built in 1847. It doubled as the official administration building back then and it remains its official headquarters today.