Roughly two blocks west of the White House is located one of the most interesting and historic architectural landmarks in the entire city, which is saying quite a bit in a city literally brimming with interesting and historic piles of stone, brick, and mortar. It's also one of the minor mysteries of Washington, D.C. It's called Octagon House and the mystery is, why, in that it only has six sides. Perhaps some writer sometime took one look, failed to count, and just assumed. Octagon House, known as the Octagon Museum today, is celebrating its 200th anniversary. It was built about the same time as the White House, and was the first private residence built in the new capital city of Washington, D.C. The Potomac River was then a mere two blocks away (now about ten blocks away). Pennsylvania Avenue was a dirt road at the time. The strangely shaped brick house sat on the corner of Eighteenth Street and New York Avenue which were barely paths chopped through the woods at a time when most of the other streets in the city existed only on paper. The "city," such as it was, mostly amounted to fields, forests, and fens (swamps).

The Octagon House was designed by Dr. William Thornton, the first architect of the Capitol, for a wealthy Virginia planter, Colonel John Tayloe III, as a winter home. Tayloe was also something of an entrepreneur and opportunist with an interest in back room politics so it was a natural choice of location what with the president living practically next door. Washington didn't grow much in the years that followed - a few stores, boarding houses, livery stables, a dairy, some law offices - all of which the British burned to the ground in 1814, including the White House. And when President James Madison and his wife Dolly returned to the city in the aftermath of the conflagration, the White House was rather black. Octagon House was about the only liveable abode in the area. It had been saved from burning by being temporarily occupied by the French Ambassador who declared it to be the French embassy. Recognising a chance to ingratiate himself with the administration, Tayloe offered his home to the president. It wasn't the White House, but it served the purpose for six months until the original could be rebuilt. And it was there, on February 17, 1815, in an upstairs oval bedroom converted to his office, where President James Madison signed the Treaty of Ghent ending the War of 1812.

After the war, in 1817, the Tayloes made the house their permanent residence and raised 15 children. The house remained in the family until 1855, after which time it became a girls' school, later a Department of the Navy office, a boarding house, and by the end of the century, little more than a tenement. Then in 1897, recognising the architectural and historic significance of the building, the American Institute of Architects leased, and later bought, the architectural landmark, renovating the rundown structure to become their national headquarters. It was within its six walls that the McMillian Commission drew up plans for clearing the Mall, where the site was selected for the Lincoln Memorial, where the first park plan for the city was created, and where the US Commission of Fine Arts was founded. And for a time, during W.W.II, it was even the home of the O.S.S., the forerunner of the C.I.A.

Today the Octagon is owned by the American Architectural Foundation, and since 1970 has been opened to the public. It houses the oldest museum in the United States devoted to architecture and design. Between 1990 and 1995, the National Historic Landmark enjoyed its fifth restoration, becoming part history museum, part art museum, and part the restored home of the Tayloes as it was during the 1820s. Yet despite all this renovation and historic research into its past, still the mystery remains, what happened to the other two sides?