The PUBLIC AUDITORIUM was opened in 1922, the fourth building completed in the MALL area. At the time, it was the largest such convention hall in the country. The auditorium was an important factor in bringing the REPUBLICAN NATL. CONVENTION to Cleveland in 1924 and 1936. In the 1930s and 1940s, its facilities made Cleveland a leading national convention center, and it continues to host numerous industrial shows every year (see also FAIRS & EXPOSITIONS). Planned before WORLD WAR I, it was financed by a bond issue in 1916, but construction was not begun until 1920. The classic Renaissance-style building was designed by city architect J. H. MacDowell, with FRANK R. WALKER as consulting architect. The combined seating capacity of the main floor and galleries of the complete hall was 11,500. The basement exhibition hall contained over 28,500 sq. ft. of space. The stage at one end of the hall is 60' x 104', with a proscenium opening 72' wide and 42' high. One of the largest pipe organs in existence is installed on the stage. In 1929 the Music Hall, seating 2,800, was added to the south end of the building. Its stage is placed back-to-back with the auditorium stage house, allowing the 2 halls to be united by the raising of a rear stagewall. An underground exhibition hall was constructed beneath the north end of the Mall and connected to the auditorium in 1932. In 1964 the entire Mall area was excavated for additional convention space and automobile parking, and a grand entrance lobby in the modern style, designed by Outcalt, Guenther, Rode & Bonebrake (see OUTCALT & GUENTHER), was built onto the west side of the auditorium. In commemoration of its early concerts held in the auditorium, many times to capacity crowds, the CLEVELAND ORCHESTRA held its 75th anniversary concert there on 12 Dec. 1993.