 CREW: At the end of the movie, the tunnel system collapses and the  buildings start to topple over. In several shots the cables used to  pull over various buildings are clearly apparent, even though it  appears that attempts were made to camouflage them with pennants.  What gives it away is that the pennants (until the buildings they  are attached to topple over) are clearly under far too much strain  to be merely hung as decorations.