Since the mid-1950s, the campus has been almost-entirely rebuilt. New facilities include three large residence halls, Worner Campus Center, Tutt Library, Olin Hall of Science and the Barnes Science Center, Honnen Ice Rink, Boettcher Health Center, Schlessman Pool, Armstrong Hall of Humanities, Palmer Hall, El Pomar Sports Center, and Packard Hall of Music and Art. The Gaslight Plaza Building, previously known as the Plaza Hotel and the Plaza Building, was purchased by the college in March 1991 and was renamed the William I. Spencer Center in public ceremonies on October 5, 1991, to honor the retiring charter trustee and board chairman. Bill Spencer served on the board from 1967 until 1991 and was chair from 1984 to 1991. The building houses development, communications, and human resources. Turn-of-the-century Bemis, Cossitt, Cutler, Montgomery, and Palmer Halls, and the William I. Spencer Center are on the National Register of Historic Places.