This is Opera (2015)

Season 1: Episode 8

Gener heads to Bayreuth, the hometown of Richard Wagner, the composer of the most ambitious operatic saga in all of musical history, "The Ring of the Nibelung". This tetralogy is made up of four operas: The Rhine Gold, The Valkyrie, Siegfried and Twilight of the Gods. Gener touches on all of them as he visits the Autostad automotive plant, walks the stage at the Bayreuther Festspielhaus (the theatre designed by Wagner himself), and converses with one of the most renowned experts on the composer.