Founded in 1188 and rebuilt several times, it became a cathedral in 1925, and thanks to its long narrow nave and elongated chancel, it is one of three longest churches in Poland (107m). Its magnificent 18C organ, carved out of dark wood and the church's undisputed pride and joy, offers an incomparably powerful sound thanks to its 7,876 pipes. Organ recitals are often packed out as a result. Admire the fine stalls and the stunning Baroque high altar, adorned with some 150 angel's heads.