I'm currently working at a fairly large complex of interconnecting buildings that - I had believed - I know well. I came down to the first floor today, stepped out of the elevator and was completely disoriented. To my right and left, about fifty feet away, were big closed metal doors. (These doors probably closed during a power failure; I've never noticed them before because they are always open, and all they do is to cordon a long hallway into segments.) I couldn't decide which way I wanted to turn to get where I was going. I picked one direction, opened the doors, glanced further, and then at last I knew where I was.
Fire doors that do not need to be kept closed are one of humanity's great inventions. The doors are held open by electromagnets that will release the doors if a fire is sensed in the building, or if power is lost. I've been in other buildings where it seems to be a godsend when these devices are installed, so we don't have to keep opening and closing the heavy fire doors all the time. (Not to mention the danger that impatient people create by blocking ordinary fire doors in the open position because they are sick of closing them.)
But today I learned that these fancy fire doors, when closed, can change the look of the building enough to be disorienting. If there had been a fire, my confusion might have been critical, and choosing to open the wrong door to find my way might have been a disaster. I'm setting out now to find all the fire doors in this place. If there ever IS a fire, I want to know what to look for.