The document discusses the post-apocalyptic genre of film. It explains that the genre revolves around disasters that destroy modern civilization. Common disasters depicted include pandemics, nuclear war, and natural disasters. The document then provides a brief history of the genre from the 1920s to current day. It notes the genre became popular in the 1970s when films drew inspiration from actual disasters. The document concludes by outlining some common subgenres like virus/zombie films and nuclear war films that involve struggles for survival in a destroyed world.