Complex sentence: It is considered to be one of the finest and most intact examples of Usonian Automatic architecture ever produced and was designated a National Historic Landmark and listed in the National Register of Historic Places on October 3,1991.
Split into simpler sentences: It is considered to be one of the finest and most intact examples of Usonian Automatic architecture ever produced. It was designated a National Historic Landmark and listed in the National Register of Historic Places on October 3,1991.