The Carnegie Mansion is a historic house located in New York City. Built between 1899 and 1901, it was the home of Andrew Carnegie, a prominent industrialist and philanthropist. The mansion features a blend of architectural styles, including Romanesque and Renaissance, and is known for its intricate details and spacious rooms. Today, the Carnegie Mansion serves as the headquarters for the Cooper Hewitt, Smithsonian Design Museum. The museum showcases design and decorative arts, offering visitors a glimpse into the history and culture of design. The mansion itself is a designated New York City Landmark and is listed on the National Register of Historic Places.