Big Brother US is well underway. Behind the scenes of the iconic house, there’s secret rooms that stretch really far down, and they’re held behind the mirrors each houseguest looks into. Creepy! As houseguests try to win Big Brother, you may think it takes little work to capture all the gossip and goings-on. They are actually surrounded by lots of hollow walls, including a crew bedroom… Big Brother’s mirrors lead to wallsLittle do some Big Brother fans know that there are lots of hollow walls behind the house’s mirrors. AI arena games are held in the house’s basement, while the upstairs diary …