These are parts of Printable Scenery's Gothic Sci-Fi building range. They come in variety of shapes with different internal/external detailing but are all married to the same theme so that you can basically just mix and match them to produce any type of building layout you'd like.
They also come in 'ruined' versions, so you can display them with holes blown in them, etc.
These were all printed on the Creality CR-10 in PLA using a 0.2mm layer height and 10% infill.
Here is the matching roof section and a shot of the interiors.
As I previously mentioned, they come in a variety of shapes, all with suitable roof sections.
These ones allow you to 'go wide' by incorporating support pillars.
Here's a corner piece. This opens up more possibilities.
And this last piece allows you to go 'super wide' by adding as many internal sections as you'd like.
A saltbeard Grognard who's glad he never grew up enough to lose his imagination.