The United States Capitol building, like Rome, wasn’t built in a day. Construction of the building actually began in 1793. When Congress, the Supreme Court and the Library of Congress moved in at the end of 1800 only the north wing, although not fully complete, was ready for occupancy. Major construction works continued gradually into the early 1960s (despite various setbacks, including the fire set by British troops in 1814, which gravely damaged the Senate wing in particular).
The model below was built in 1903-1904 as part of a study by the Architect of the Capitol for the purpose of building the East Front Extension of the Capitol, completed in 1962. It has been in the basement rotunda of the Canon Office Building since 1976.
The exhibit’s label reads:
This study model in plaster in a scale of 1/5 inch = 1 foot was constructed by Emile Garet, an architect sculptor, for the Architect of the Capitol as part of a 1904 report for the extension of the East Front of the U.S. Capitol. It was constructed so that the extension could be removed to compare the Capitol as it then existed with the proposed changes of 1904. The delicate carvings and attention to detail made this model a popular attraction at international expositions in the early 20th century. It was displayed in the crypt of the Capitol from 1938 to 1976, when it was moved to this location. The extension of the East Front was ultimately constructed between 1958 and 1962.