I posted a picture of the scenery loading door to the Colosseum a while ago. Here is another from the Cambridge Theatre, again where the compactness of the site in London’s West End means that when the door is open you get a view from the street directly into the side of the stage.

The column for a Marks Barfield spectacle on Brighton Seafront. The stages are inserted at the base and then lifted to make space (underneath) for the next section.