The SciFi genre has been popular since the early 1900s but became widely popular after Stanley Kubrick's 1968 film "2001: A Space Odyssey". Throughout the 1970s and 80s, many classic SciFi films were released and helped commercialize the genre. Common SciFi themes include alien invasions, time travel, robots vs. humans, and questioning humanity. Iconic directors and actors like Ridley Scott, Steven Spielberg, and Arnold Schwarzenegger are regularly featured in big-budget SciFi films. Blade Runner from 1982 is considered one of the greatest SciFi films of all time despite its depiction of a dystopian future.