The famous play "R.U.R." is Czech author Karel Capek's masterpiece. R.U.R. stands for Rossum's Universal Robots, and introduced the word "robot" to the English language and to science fiction as a whole. The play begins in a factory that makes artificial people called "robots". Unlike the modern usage of the term, these creatures are closer to the modern idea of androids or even clones, as they can be mistaken for humans and can think for themselves. They seem happy to work for humans, although that changes and a hostile robot rebellion threatens the extinction of the human race.