In the mid-1950s, the Black Mesa New Mexico facility that would become central to almost all of Keenan Lane's interests was built. It is situated within, atop, and surrounding an actual mesa in the scrub deserts near Albuquerque NM. It is a massive locale, at its peak able to sustain itself by the hydroelectric power produced by its dammed reservoir, as well as a nuclear power plant - and very likely some less conventional power sources. Typically, around nine thousand people worked as well as lived in the facility. Families lived in provided housing, though the children went to school in a nearby facility outside the actual research structure. It has its own rail system, both old and new, plus after the Events and far more after the demise of Ulathoi it also incorporates teleportation as a normal method of traversing the interior.
The inside of the facility had been maintained at specific temperatures, usually much cooler than the exterior could get. By the very nature of having a huge, hollow interior, the mesa's temperature is easily regulated. However, there are spots within it that are still too dangerously flooded, too toxic from waste spills, or radioactive from incidents at the power plant, to safely travel. Over time, those locations will be patched up, fixed or completely isolated.
The bulk of the Half Life game, as well as much of Repurposed, takes place within this facility both before and after its change of name from Research Facility to Refugee City. I've tried to emulate the look and feel of locations found there, in the base.
The main power plant for the Convocation base is situated within the Black Mesa area. In it, a number of overwhelming and dangerous machines are found - a catwalk, completely enclosed in most spots, allows for observation. A security system scans any potential visitors to the next area. [In deference to the many, many points in Half Life, Portal and Fear where the character must make their way through air vents and crawl spaces, there is an honorary crawl space along the northern wall - not visible in this image.]
The Anti-Mass Spectrometer - this is where everything began, at least in Half Life. The bright orange and graphite coloration, as well as the many sparking and shiny displays might distract from its purpose. It had one purpose: to blow up. That fateful day that Gordon Freeman wheeled in an 'exceptionally pure' sample from Xen, the right nudge at the wrong time made all the difference in their world. Alma's sheer destructive Vortal power gave that nudge more than 1500 miles away, shaking the very foundation of the world. Once the Resonance Cascade was begun, nothing could stop it. It allowed creatures from Xen - and more distant dimensions - to hop into this world. It also allowed Gordon Freeman to do his destined work: to free Vortikind, and start a new era.
The Lambda Teleporter - the most functional portion of the Convocation base is its teleporter. Here, the idea of the old over-budget Lambda labs devices have been updated by the Pantheon as well as incorporating the distinct Combine technology. Together they power teleporters which can reach distant parts of the city, as well as other worldly destinations alike. That green ball in the middle? Not Hamidon. That's Lane. Teleporting. [yeah I know it's a hami ball - but it IS the same distinct color that Keenan's teleportation *should look like*. And he inspired the teleportation lab.]
The Black Mesa Observation Deck - this is simply inspired by all the fun places in Black Mesa you can explore. There's a lunch room, offices, and a spare portal just in case anyone needs it. Note the lack of hand rails on the stairs. That's a 'feature' of many portions of Black Mesa as well as other locations. OSHA would have a fit.
Directly south of this room is the 'Vortal Doorway' which is simply an unused black corridor between 'worlds'.
Keenan Lane's office entryway is also technically part of Black Mesa. It is detailed in the Xen page.