I would have liked this image a whole lot more had there not been a person in the center. She seems out of place, and in my opinion is distracting to the architectural aspect of the image.
clever image. great tonal quaity. not sure whether an adult makes the best subject here - the position of model is very central to the opening (child head peeping over might have been more interesting).
your model doesn't look too happy... is it going forward in time? (",) kidding, I'd like to know what kind of contraption that is, looks weird, but you've gotten a nice angle on it.