<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2010) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2010) (Learn how and when to remove this template message) </Td> </Tr> <P> In Arthur C. Clarke's Space Odyssey, monoliths are machines built by an unseen extraterrestrial species . In the series of novels (and the films based on these), three monoliths are discovered in the solar system by humans . (It is also revealed that thousands of others, if not more, exist elsewhere in the solar system .) The response of the characters to their discovery drives the plot of the series . It also influences the fictional history of the series, particularly by encouraging humankind to progress with technological development and space travel . </P> <P> The first monolith appears at the beginning of the story, set in prehistoric times . It is discovered by a group of hominids and somehow triggers a considerable shift in evolution, starting with the ability to use tools and weaponry . </P>

What is a monolith in 2001 a space odyssey