'Die Walkure'' (the Valkyries) is the second of the four works that make up the "Der Ring des Nibelungen" (The Ring of the Nibelung). It premiered in Munich in 1870. The "Ride of the Valkyries" is definitely the best-known piece from this opera and perhaps the most famous of all Wagner's works. It was also used as the soundtrack during the helicopter attack in Francis Ford Coppola's film "Apocalypse Now".
