Terrace Hill

Terrace Hill, also known as Hubbell Mansion, Benjamin F. Allen House or the Iowa Governor's Mansion, is the official residence of the governor of Iowa, United States. Located at 2300 Grand Avenue in Des Moines, it is an example of Second Empire architecture. The home measures 18,000 square feet. It sits on a hill overlooking downtown Des Moines, and has a 90-foot tower that offers a commanding view of the city. The building's steeply pitched mansard roof, open verandas, long and narrow and frequently paired windows, and bracketed eaves give this house an irreplaceable design. The house was designated a National Historic Landmark in 2003.

Source: Wikipedia