What I see through front door of my Spanish teacher's apartment

I like this photo because it is really strange for me to see this. He lives in a type of property that is called Propiedad Horizontal or horizontal property. There is a common front door (or in his case 2 doors - one made of wood and the other of glass) and behind this there is a long (and narrow) hallway. In the back there are three other doors to three individual apartments. Very interesting.