In Ithaca, I once tried collecting second-floor doors that led nowhere. There's a great one on Cascadilla, and a whole apartment building's back full of them overlooking Spencer. I've forgotten where the others were; you might say it was a highly ephemeral collection. To count as a door going nowhere, a door had to be something that had once been functional but that now would pitch anyone trying to use it down a sheer drop, cartoon-style.
On an unusual way home after work tonight, I passed this one, on the side of one of our campus officehousebuildings. I had been looking up to the second-floor lit office of a colleague in that department, admiring his book collection and his geraniums (geraniums? apparently blooming, in mid-January?), and as I proceeded along the path, I was still looking up and managed to see what I know I've seen before but forgotten: that we too (in a collective, collegiate sense) have a door going nowhere. I taught in this building last spring; that door is poised in the landing of the building's main staircase, for no obvious purpose.
Why do these doors intrigue me so much? I suppose it's simply because they're there, even though they're obviously no longer doing anything. Generally, they're not even lovely doors; this one, for instance, is a fairly run-of-the-mill door. And yet, if you look closely, you can see that it actually still has a storm (or screen) door, replete with handle. It's as though a stairway or balcony simply vanished one night, and no one knew what to do with the door that was left behind to signal that once there had been more material, more purpose. I find something melancholically insufficient about a perpetually suspended, perpetually useless door. It is a thing without a mission, a material reminder of its structure's past lives. It is a ghost door.