4. William Starr Miller II’s Mansion, 1048 5th Ave.
Another mansion-turned-museum is the former estate of industrialist William Starr Miller II. Designed by the illustrious firm of Carrère & Hastings (the duo who designed the New York Public Library), it was completed in 1914. Later the home of Grace Vanderbilt, wife of Cornelius Vanderbilt III, the home is now the Neue Galerie, a museum full of German and Austrian art. The museum is temporarily closed for renovations but will soon re-open on August 31st, 2023.