In 1928, Fritz Lang made the film "Spies" which contained many tropes that became popular in later spy dramas, including secret headquarters, an agent known by a number, and the beautiful foreign agent who comes to love the hero. Lang's Dr. Mabuse films from the period also contain elements of spy thrillers, though the central character is a criminal mastermind only interested in espionage for profit. Additionally, several of Lang's American films, such as "Hangmen Also Die", deal with spies during World War II.