[piasa]

If they weren’t allowed in that area of the building then how did they not only conclude there was an underground cellar but also make the assumption of how it was used?

[CedarDave]

If they weren’t allowed in that area of the building then how did they not only conclude there was an underground cellar but also make the assumption of how it was used?

See the excerpt below and click the link for the entire story. Notice that in my post I used the work "supposedly" as none of this has been verified - rumors and unconfirmed stories.

... an underground level described by one IT contractor as a “dungeon” outfitted with surveillance cameras. Reports from maintenance workers and visitors detail hidden tunnels, underground rooms, and even a “fertility room” equipped for medical procedures.