I'm so glad I found people to share this adventure with. Let me tell you about my Thornhill's story:
Last year I saw a London Victorian mansion for sale for about $7M. The was titled "a house that can fly." The owners had restored it to its original glory both inside and out, except for the attic space. The attic was converted into a spaceship cockpit. It was so cool that they indulged their kids with this fantasy. (Google 'house with spaceship attic') And since I've loved science fiction since I was a teen, I decided to pretend that my Thornhill is really a spaceship, and even better that it's a time machine. I added two floors under house for a glorious two story entrance hall with double staircase, dining room, living room and kitchen. AND under that, underground is a grotto complete with swimming pool. I can't wait to display my renovation plans.