The Old Patent Office Building

The historic Old Patent Office Building in Washington, D.C. covers an entire city block defined by F and G Streets and 7th and 9th Streets NW. Designed in the Greek Revival style by architect Robert Mills, construction started in 1836, and took 31 years to complete. United States patent law required inventors to submit scale models of their inventions, which were retained by the Patent Office and required a place to house them. After undergoing extensive renovations, the building reopened on July 1, 2006. The building currently houses two Smithsonian Institution museums: the National Portrait Gallery and the Smithsonian American Art Museum. --From Wikipedia.