The reason that certain government buildings don't have windows in secure spaces, is that spy agencies can use lasers pointed at the windows, and from those vibrations detectable by the lasers, they can make out what is said in the room. Just amazing how sci fi.
Similar to the old Israeli trick to visually measure the vibrations of a hanging lightbulb to capture the sounds in a room.
Soviets did that using windows of rooms where meetings were taking place. Im sure there's more than a few cold war methods of doing this.
The reason that certain government buildings don't have windows in secure spaces, is that spy agencies can use lasers pointed at the windows, and from those vibrations detectable by the lasers, they can make out what is said in the room. Just amazing how sci fi.