This is based on the Hirst Arts Ruined Tower. I found a model of it and several other Hirst Arts buildings on the Sketchup warehouse site, but none of them were manifold and I couldn't get any to be remotely printable.

I used the floor plans for the original (admittedly without permission) and inkscape to get the base of the tower. Everything else after that is best guess dimensions and a little creative liberty in Solid Works. I left the stairs off, I may just make a ladder... or come back and add it later. I've broken it out into sections for printing.