Antony Dracup was an artist who did something that I've sometimes toyed with (but never taken further):- he extended a small cave accessed from his back garden into a vast palace:-
Antony kept chiselling by hand day after day until he achieved a masterpiece in the cave below his house. Antony died in 2002, and his son Dennis is now selling the cave + house.
It is remarkably like the Tardis (bigger on the inside than the outside):-
--------- Alex Kemp