The Tucson Symphony Orchestra, or TSO, is the primary professional orchestra of Tucson, Arizona. Founded in 1928, when the season consisted of just two concerts, the TSO is the oldest continuously running performing arts organization in the Southwest. The TSO's season now runs from September to May and consists of over 60 concerts, including a Classics Series of eight programs, a Pops Series of four programs, a Masterworks series of five chamber orchestra programs, a number of one-night only specials, and run-out concerts to surrounding areas, such as Oro Valley, Green Valley, Bisbee, Safford, Thatcher, and Nogales. The TSO also provides educational programming that reaches over 40,000 school children each season. Within the TSO are a number of standing chamber ensembles, including a string quintet, piano trio, harp trio, brass quintet, and woodwind quintet. These ensembles help provide educational programming through school visits, perform recitals annually, and also perform at private and community events.