The Vienna Opera is a magnificent building.  During the course of a year they present 60 different productions, 50% more than the second-place finisher, Munich.  As a result, the Vienna Operahouse always buzzes with activity.  Here, stagehands are getting ready for the next production, hanging scenery, making sure all the hoists will lift and drop on cue.
If you look closely at this picture you will notice that the stage area is very deep.  In fact, there is more floor space behind the footlights than there is on this side.