Plans that never worked out.
Proposed design for the US Capitol with high dome by William Thornton, c. 1797. Credit: Library of Congress, Prints and Photographs Division, LC-DIG-ppmsca-19858 
Competition entry for the Presidentâ??s House, by A.Z. (attributed to Thomas Jefferson), 1792. Strong historical evidence indicates that this design, submitted under the initials A.Z., was actually by Thomas Jefferson. Credit: Courtesy of the Maryland Historical Society, 1976.88.6 
Plan for the National Mall by Andrew Jackson Downing, 1851. CREDIT: National Archives. 
Projected improvements to the Washington Monument and National Mall by B.F. Smith, 1852. This image shows a variation on the circular colonnade that was part of the original design for the Washington Monument, but was never executed. It also shows a proposed suspension bridge across the canal adjacent to the Mall. Credit: Library of Congress, Prints and Photographs Division, LC-DIG-ppmsca-31534 
Competition entry for the Library of Congress by Leon Beaver, 1873. Credit: Library of Congress, Prints and Photographs Division, LC-DIG-ppmsca-31512 
Competition entry for the Library of Congress by Alexander R. Esty, c. 1880. This proposal for the Library of Congress was an unusual application of the Gothic Revival style. Credit: Library of Congress, Prints & Photographs Division, LC-DIG-ppmsca-31519 
Proposed Memorial Bridge in Honor of General U.S. Grant by Smithmeyer & Pelz, 1887. The proposed site was roughly the same as the current site of the Memorial Bridge. Credit: Library of Congress, Prints and Photographs Division, LC-DIG-ppmsca-31532 
Proposal for the completion of the Washington Monument by Vinnie Ream Hoxie, c. 1876-78. Construction of the Washington Monument began in 1848 but was halted in 1856, leaving an unfinished stump on the National Mall for more than two decades. In the 1870s, various architects and others proposed ideas for finishing the monument, often in unexpected ways. Credit: Library of Congress, Prints & Photographs Division, LC-USZ62-113998 
Proposed Executive Mansion on Meridian Hill by Paul J. Pelz, 1898. Mary Foote Henderson, wife of a former U.S. senator, commissioned architect Paul Pelz to design this palatial replacement for the White House for a site on Meridian Hill, directly across the street from the Hendersons own mansion. Credit: Library of Congress, Prints & Photographs Division, LC-DIG-ppmsca-31528 own mansion. Credit: Library of Congress, Prints & Photographs Division, LC-DIG-ppmsca-31528 
Winning Competition Entry for the Washington Monument by Robert Mills, 1846. Mills original proposal called for an obelisk anchored by a circular, Greek-inspired temple at the base. The base was never executed, and the proportions of the obelisk itself were changed when the structure was finally completed nearly four decades after this drawing was produced. Credit: Library of Congress, Prints & Photographs Division, LC-DIG-pga-03714 original proposal called for an obelisk anchored by a circular, Greek-inspired temple at the base. The base was never executed, and the proportions of the obelisk itself were changed when the structure was finally completed nearly four decades after this drawing was produced. Credit: Library of Congress, Prints & Photographs Division, LC-DIG-pga-03714 
Design for National Galleries of History and Art by Franklin Webster Smith, 1900. The project would have stretched from 17th Street, near the White House, all the way to the Potomac River. Credit: National Galleries of History and Art: The Aggrandizement of Washington (F.W. Smith, 1900) 
Plan for the National Mall — Rendering of the Proposal for the Washington Monument grounds, by the Senate Park Commission, 1901-02.The wide steps, the circular pool, and the terraced gardens were all intended to provide a more dignified base for the monument, while resolving the awkward geometry resulting from its placement off the axis from the White House. Credit: Courtesy of the U.S. Commission of Fine Arts 
Rendering of the proposed National Sofa, to be located across Pennsylvania Avenue from the White House, by Jim Allegro, AIA, and Doug Michels, 1996. Allegro and Michels were concerned that the closure of Pennsylvania Avenue following the Oklahoma City bombing would further isolate the presidency from the people. They proposed the National Sofa as a place of virtual and physical interaction to address that gap. Credit: Copyright James Allegro, AIA and Doug Michels