The Boston Symphony Orchestra (BSO) is an American orchestra based in Boston, Massachusetts. It is one of the five major American symphony orchestras commonly referred to as the "Big Five". Founded in 1881, the BSO plays most of its concerts at Boston's Symphony Hall and in the summer performs at Tanglewood. Andris Nelsons is the current music director of the BSO. Bernard Haitink currently holds the title of conductor emeritus of the BSO, and Seiji Ozawa has the title of BSO music director laureate.