living in each room, tenement-apartment-style. The residents were probably mostly workers in the factories that populated Foggy Bottom. In 1898, the American Institute of Architects (AIA) selected the Octagon to be their new national headquarters. They rented the building for 4 years, and then purchased it outright in 1902. The Octagon would continue to serve as AIA's headquarters until the construction of the current headquarters building in the 1960s. Museum The Octagon opened as a museum in 1970. The museum was restored to its 1817–18 era appearance in the early 1990s—the wall colors and room configurations that you see today are representative of that time period. The museum was administered by the American Architectural Foundation from 1970 to 2011/2012 (though the museum was closed from 2007 through 2013). Today, the museum is administered by the American Institute of Architects Foundation, and offers self-guided tours, permanent and changing exhibitions, public programming, and guided tours by appointment. It was declared a National Historic Landmark in 1960. Architectural details The three-story brick house, adapted to an irregular-shaped lot, displays a dramatic break with the traditional, late Georgian and early Federal house planning that preceded it. The Octagon achieves a zenith in Federal architecture in the United States, through a plan which combines a circle, two rectangles, and a triangle, and through the elegance and restraint of the interior and exterior decoration. The Coade stone, stoves, other decorative elements, and furniture were imported from England. The construction materials, such as bricks, timber, iron, and Aquia Creek sandstone were all manufactured locally. The reason behind the naming of the six-sided building as the Octagon is unknown. Though the main room is a circle, one possibility is that it resembled octagonal rooms common in England, which were also circles but called octagon salons because they were constructed of eight walls and then plastered heavily in the corners to make a circle. Another explanation is that the eight angles formed by the odd shape of the six walls are an old definition of an octagon. Alleged haunting The Octagon House is purported to be one of the most haunted homes in D.C. Apparitions and the presence of otherworldly forces have reportedly been seen and felt in many places at The Octagon, including on the spiral staircase, the second floor landing, the third floor landing, the third floor bedroom, and the garden area in the rear. Among the