The Portland Flats (later known as the Portland Hotel) was the first luxury apartment building constructed in Washington, D.C. Construction of the elaborate building, designed by architect Adolf Cluss, was completed in 1881. It was built on the south side of Thomas Circle, a traffic circle and park where 14th Street NW, M Street NW, Massachusetts Avenue NW, and Vermont Avenue NW intersect. The triangular-shaped building's main architectural feature was the corner tower and dome, which resulted in the Portland Flats resembling an ocean liner sailing into Thomas Circle.