The office building, where I work, had a show case data center room adjacent to the main lobby, complete with large windows. When my current employer took out the lease on the building, the VP of IT decided to use that room for as our data center, partly because it already had the required AC and electrical, and also because the door was right next to the security desk. To get in or out, you need both a properly authorized access card and for the guard on duty to know and recognize you. (The entry is airlock-style, so anyone trying to exit that the guard doesn't recognize is contained while the guard contacts a higher authority. Also, the windows are now covered, except for the door windows.)