Teatro Nacional de São Carlos (São Carlos Opera House) was inaugurated on 30th June 1793 and is still today the only Portuguese theatre devoted to producing and presenting opera, choral and symphonic music. With an existence full of relevant historic facts, social episodes and cultural events which enrich its distinctive historic heritage, its 18 th century neoclassical building of Italian influence was classified in 1928 as National Monument. The Coro do Teatro Nacional de São Carlos (São Carlos National Theatre Chorus), formed in 1943 and the only professional choral structure in Portugal, performs the great operatic and choral-symphonic repertoire and the Orquestra Sinfónica Portuguesa (Portuguese Symphony Orchestra), founded in 1993, are the two resident artistic groups. The Theatre's regular music programme is shown in three spaces: the Main Hall destined to great operatic productions, concerts and dance. The Salão Nobre (Grand Hall), the ideal place for more intimate performances such as recitals, chamber opera and music or conferences on opera and music and the Foyer at the entrance to the Theatre, is a favourite place also for social gatherings, chamber concerts and recitals with free admittance. Teatro Nacional de São Carlos also promotes and holds meetings, conferences, master classes, courses, concerts by/for schools and families and a wide variety of cultural proposals. At the end of each season the Theatre organizes the Festival ao Largo (at the São Carlos Square, just in front of its building). For about one month open-air performances of opera, theatre, symphonic music and choral-symphonic music, dance, among other artistic manifestations are held in a festive celebration of music and performing arts. With free admittance, all the performances are commented, thereby ensuring mediation with different audiences.