Oh, I would LOVE to have a round room like that in the corner of my home. Of course, it has to have a domed ceiling and a few porthole windows.
I also wouldn't mind having a dark and narrow tower like this as one of the features of my home. I would slowly and cautiously walk up and down the tightly wound stairs with only a small candle for my light.
All these buildings are in Lyon. First two are in Presqu'île; the last one in Vieux Lyon by the Metro Vieux Lyon station (I think it's part of the Bibliothèque 5eme). Aren't they delicious????