Black Mesa Research Facility

For other places called Black Mesa, see Black Mesa
The Black Mesa Research Facility is a fictional facility where most of the events of the computer game Half-Life take place. The facility is built over a decommissioned missile silo in the New Mexico desert. Much of the research undertaken there is deliberately left vague, but it is apparently funded by the United States government and engaged in highly-classified research involving radiation, extra-dimensional travel, rocketry and weapons development. As revealed in the game's introduction, at the time of the events in Half-Life, they are seeking employees with backgrounds in theoretical physics. It is unclear as to if there is any kind of military garrison at Black Mesa, the reason for thinking so the Apache seen in one of the train sequences. This could just be foreshadowing for the plot of the game.
The physical range of the facility is, from an in-game perspective, nothing short of massive. It is also apparently self-sufficient, housing its own power generation systems including a hydroelectric dam, multi-story car parks, nuclear and conventional arsenals, a local electric rail transport network, laboratories housing the latest equipment for every conceivable high-tech scientific discipline including a powerful mass spectrometer, and even its own rocket launch site. It can be inferred that the facility is somewhat old considering that some areas have been described by the in-game characters as "old and abandoned". The facility is largely destroyed by a nuclear warhead at the end of the expansion pack .