German expressionism began in Germany in the early 20th century with films like Der student von Prag in 1913 but World War I isolated German filmmakers, allowing the style to develop independently. German expressionism emphasized expression over narrative through techniques like contrasting light and dark and abstract architectural designs. It flourished in the 1920s but declined after the Nazis rose to power, though it influenced later genres, including American film noir. Film noir heroes are typically flawed men with dark pasts who understand the cynical world but are undone by femme fatales they become involved with.