UFO: Enemy Unknown (marketed as X-COM: UFO Defense in North America) is a science fiction strategy video game developed by Mythos Games and MicroProse.
The game begins on January 1, 1999, with the player choosing a location for their first base on the Geoscape screen: a global view representation of Earth as seen from space (displaying X-COM bases and aircraft, detected UFOs, alien bases, and sites of alien activity).