Smithsonian Museum Building, the Castle

The Smithsonian Building, often referred to as the castle, is the original Smithsonian building on the National Mall.  

The name, Smithsonian, come from the original donor for the construction of the museum as we know it today.

James Smithson, and Englishman, and someone who never visited the United States,in the late 1820's,  left his fortune to the United States for the advancement of science and knowledge.