The Glee Club, Princeton's oldest choir, began in 1874 with a handful of students and now numbers more than 80 talented singers who perform around the world. A cappella groups, which sprang up in the 1930s as an alternative to the Glee Club, are one of the University's most enduring traditions and now number well over a dozen — specializing in genres from pop to classical to contemporary. They are frequently heard harmonizing under Blair Arch or one of the many other stone arches on campus which provide acoustically desirable venues for the singers to hone their pitch and performances.