The opera has a main level with the stage, and a second one with a balcony. There's also a small basement with a secret room. There are three versions of the map: one with grid and numbers to denote locations (left to the keeper to determine), one with grid but without the numbers, and one without grid or numbers. It has a nice hand-drawn feel to it.
There is quite a bit of detail in the maps, and it looks like the real European opera houses.
Only real complaint I have is there is no scale, but it's easy enough to determine from the context (e.g. door width).
I'm certain this will make for a great set piece for a climactic encounter for a Cthulhu game session. And the price is very reasonable!