13.3" x 13.3" (338mm x 338mm) footprint. Stackable structure can built as a single unit (floors glued together) or as individual modules so you can stack and unstack as you wish. The minimum pieces you'll need are a ground floor and a top floor, but you can also add as many middle floors as you like to make a structure as tall as you want.
Generic design should fit well in most regions of the world and most time periods from WWII forward and into the future!
Note: Product photos are of the 15mm version of this kit. Design of the 20mm version is identical except larger.
