Dietrich was a German actress and singer. Abandoning an early ambition to be a violinist, she turned to acting and gained international attention as a femme fatale in The Blue Angel (1930). She then moved to Hollywood, where she starred in a series of films that established her glamorous and sophisticated persona. Resisting Nazi pressure to return to Germany, she became a US citizen in 1939. During WWII, she regularly entertained Allied troops, appearing before them how many times? Discuss