John Henry Hammond House

[1] Carnegie sold off lots to individuals who agreed to build substantial dwellings, and in 1903, a home was built at 9 East 91st Street by John H. Hammond, a New York City banker.

[3] The design of the limestone-clad building, which unusually for a Manhattan town house offers a finished side elevation as well as its street front, is strongly influenced by 16th- and 18th-century Italian palazzo details.

[4] Interior photos from the early 20th century display a "rich series of Louis XVI-style rooms with elaborate marbles, carving, tapestries and furnishings.

[1][3] Under Castroviejo's ownership the house hosted lavish parties for celebrities including British actress Hermione Gingold and Spanish Catalan operatic soprano Victoria de los Ángeles.

[3] In 1974, over objections from Castroviejo, the New York City Landmarks Preservation Commission designated the building as part of the Carnegie Hill Historic District.

[1] The Soviets also received permission to install a large wrought-iron gate around the mansion and closed-circuit cameras to watch over the street in front of the building.