This is my contribution to the wargaming community here on thingiverse! :)
It is a 3D Printable modular terrain set.
You will need 12x 3mm diameter x 2mm deep magnets & 2x 5mm x 2mm magnets for the pillars. For each complete floor & wall you will need 4x 3mm x 2mm magnets. The broken ones will either take 3 or 2 each depending.
The only problem we have found is that sometimes we have too much fun assembling it rather than actually fighting the battles! XD
Once assembled it is really strong and can hold metal figurines easily.
Painting done by my bro, check out his work on instagram: https://www.instagram.com/theforgotten3rd/
If you like this style of modular scenery be sure check out aaskedall's designs, which are similar to mine, but work with printed slots and not magnets.
Edit - 25/11/19
I have added a large window. I found I had trouble printing it upright without supports so I created a flat version allowing for easier prints.
edit - 8/12/19
I have created a modular base system for the ruins, if wanted.
You may need to clean out some of the holes with a 3mm or 5mm drill bit/screwdriver if you find your magnets do not fit in easily. I found I had to do this occasionally.
I recommend magnetising the pillars alternating the top and the bottom of each wall & Pillar, so that they can stack together for storage.
To make 4 reasonably sized ruins I'd suggest around 50-60 pillars, 30 full windows, 15-20 Broken windows, 15 solid floors, 10 broken floors, 30 arches, 15-20 broken pillars. Along with say 10 balconies and cap pieces.