Complex sentence: "It Happened in Sun Valley" is a 1941 song composed by Harry Warren, music, and Mack Gordon, lyrics, which was recorded and featured by Glenn Miller and his Orchestra in the movie "Sun Valley Serenade".
Split into simpler sentences: It Happened in Sun Valley is a 1941 song composed by Harry Warren and with lyrics by Mack Gordon. It was recorded and featured by Glenn Miller and his Orchestra in the movie "Sun Valley Serenade".