The Cathedral of Learning is a 42-story skyscraper that serves as the centerpiece of the University of Pittsburgh's (Pitt) main campus in the Oakland neighborhood of Pittsburgh, Pennsylvania. Standing at , the 42-story Late Gothic Revival Cathedral is the tallest educational building in the Western Hemisphere and the second-tallest university building (fifth-tallest educationally-purposed building) in the world, after the main building of Moscow State University. It is also the second-tallest gothic-styled building in the world, after the Woolworth Building in Manhattan. The Cathedral of Learning was commissioned in 1921 and ground was broken in 1926 under general contractor Stone & Webster. The first class was held in the building in 1931 and its exterior finished in October 1934, prior to its formal dedication in June 1937. It is a Pittsburgh landmark listed in the National Register of Historic Places. Colloquially referred to as "Cathy" by Pitt students, the Cathedral of Learning is a steel frame structure overlaid with Indiana limestone and contains more than 2,000 rooms and windows. It functions as a primary classroom and administrative center of the university, and is home to the Dietrich School of Arts and Sciences, the School of Social Work, and many of its departments, as well as the University Honors College. It houses many specialty spaces, including a studio theater, food court, study lounges, offices, computer and language labs, 31 Nationality Rooms, and a half-acre (2000 m2, 22,000 ft2), 4-story-high, vaulted, gothic study and event hall. The building contains noted examples of stained glass, stone, wood, and iron work and is often used by the university in photographs, postcards, and other advertisements. Use The basement and floors up to (and including) floor 40 are used for educational purposes, although most floors above 36 house the building's mechanical equipment. These floors include theaters, computer laboratories, language laboratories, classrooms, and departmental offices. The basement contains a black box theater and the ground floor contains computer labs, language labs, classrooms, and the Cathedral Café food court. The lobby, comprising the first through third floors, contains a massive gothic Commons Room that is used as a general study area and for special events and is ringed by three floors of classrooms, including, on the first and third floors, the 31 Nationality Rooms designed by members of Pittsburgh's ethnic communities in the styles of different nations and ethnic groups. Twenty-nine of these serve as functional classrooms while more