Residence of the Ambassador of Colombia to the U.S. (Thomas T. Gaff House)

From www.colombiaemb.org:

Gaff, a wealthy midwestern businessman, had the house built as the primary residence for he and his wife, Zaidee. He had made his fortune in the distillery and heavy machinery businesses in Cincinnati, Ohio. Jules Henri de Sibour was a prominent architect for the famous and wealthy in Washington at the time, and would design homes that would eventually become residences of the ambassadors of France, Luxembourg, and Portugal.

Gaff had the architects design novel conveniences into the mansion's traditional aesthetic including a hot- air system for drying clothes, a trapdoor on his icehouse for direct delivery from the street, cork insulation for the wine cellar, and a movable wooden wall that close off the domed and sky lit Edwardian ballroom. The dining room was designed with Elizabethan wainscoting and a sideboard originating from an Italian monastery.

Following the short occupation of the house by the Gaff family, they leased it to several prominent Washingtonians, including President Calvin Coolidge's Secretary of War, Dwight F. Davis, and to the governments of Greece and Colombia. The Colombian government purchased the house in 1944 from Thomas Gaff's daughter, Mrs. Carey D. Langhorne, who lived next door on Q Street at the time. Since then, it has served as the official residence for the Colombian Ambassador to the United States.