Here's what happened when they played a show inside a church in Belgium: The church had to take a special insurance on their windows, and during the sound check some windows did get cracks in them. The entire church, which was of the large, high kind, was so filled with smoke it was impossible to see the band play if you where more then four meters away from them. The pressure of the sound was strong and constant enough so that somebody actually fell forward when they stopped playing. The CMOA? This wasn't actually that special for a Sunn O))) show.