There are currently 33 undergraduate residence halls at the University of Notre Dame, including 32 active residence halls and Zahm Hall, which serves as a transition dorm when residence halls undergo construction. Several of the halls are historic buildings which are listed on the National Register of Historic Places. Each residence hall is single-sex, with 17 all-male residence halls and 15 all-female residence halls. Notre Dame residence halls feature a mixed residential college and house system, where residence halls are the center of the student life and some academic teaching; most students stay at the same hall for most of their undergraduate studies. Each hall has its own traditions, events, mascot, sports teams, shield, motto, and dorm pride. The university also hosts Old College,