The Half-Life series of video games features many locations set in a dystopian future stemming from the events of the first game, Half-Life. These locations are used and referred to throughout the series. The locations, for the most part, are designed and modeled from real-world equivalent locations in Eastern Europe, but also include science fiction settings including the Black Mesa Research Facility, a labyrinthine subterranean research complex, and Xen, an alien dimension.