I always wanted a space like that to make a sweet pad for my dog, with a fire-hydrant lamp, photos on the wall of his dog friends and comfy bed, small corner fireplace etc...
Judging by the spacing of the bannister rails that space looks to be ~36x30. My dog's bed is 26" across, leaving plenty of room for the other stuff. I mean look for a dollhouse fireplace on line, they're pretty small, and the lamp could just be a rubber fire hydrant toy with the lamp mount jammed in.