Loosely based on Wolfram von Eschenbach’s Parzival—the medieval epic poem of the Arthurian knight Parzival and his quest for the Holy Grail—Parsifal is a three-act opera by German composer Richard Wagner. The opera was first conceived in 1857 but not completed until 25 years later. It premiered in 1882 at the second Bayreuth Festival, where it was performed exclusively until 1903. What tradition has arisen among the audience at performances of Parsifal at Bayreuth? Discuss