The Smithsonian Institution, established in 1846 “for the increase and diffusion of knowledge”, is a group of museums and research centers administered by the United States government. Termed “the nation’s attic” for its eclectic holdings of 137 million items, the Institution’s Washington, D.C. nucleus of nineteen museums, nine research centers, and zoo—many of them historical or architectural landmarks—is the largest such complex in the world.