This is my current diorama in 1/35th scale. It is large, 8 feet by 4 feet, comparable to several others I have built in the last 40 years. (152.4cm X 243.84cm). None of the structures in these photos are finished. It will have 50 vehicles including a locomotive and RR gun, and around 350 figures. I call it "Logistics". This first shot is of the front of the diorama, A train shed that leads to the Train station will have a locomotive, tender and K-5e rail gun. The canopy will span the front and will be intact in some places and collapsed in others. The building above in the foreground is a large beer hall.

Here is a bombed out building that will show all the way down to the basement.

A statue of Hermann Von Balke in the plaza. On the left is Old Town.

This is the Kaufhalle, (Dept.store). It is a total ruin and the largest and most complicated building in the dio.

Part of the bomb blasts in the department store. there is bomb damage to most of the buildings.

I set a deuce and a half in the street to give some perspective. I will be putting pounds of rubble throughout the dio.
I will show how I make the buildings. I begin by cutting corrugated cardboard shapes for the building facade. This building will house a Roman/German Historical museum.
After the facade is assembled, the lower part of the building is purposely too long. That is because when I build the base, I start with a wooden frame. I screw a sheet of plywood onto the bottom, then vary the heights of the framing and the interior bracing. I use model rail road board to "skin" the top which will then have a rolling hill effect that will vary from place to place by as little as one inch, (25mm), and as much as 12 inches, (300mm). It gives the diorama that extra effect of topography. Cities built on a perfectly flat terrain are rare.
Here is the matt board cut outs ready to be veneered to the corrugated cardboard facade.
Here is a shot of the base of "Logistics" and the square, triangular and rectangular holes cut for placement of the buildings. The buildings will then set down into those holes and I can be assured of their being "true" to the base. The large hole on the far right will be the resting place for this building.
Next, I cut the matt board, a material found in either framing shops or art supply stores, to the shape and then veneer them to the corrugated cardboard structure using carpenters glue. The strength this gives the structure is surprising. That is the part that will lower into the hole on the base and rest on the plywood beneath.
The mosaic on the gable was made with Milliput and several Andrea 25 mm Roman figures. After a coat of plaster on the entire building and the stones are then engraved in the plaster.
Here is a close up of the gable.
Here is the base coated facade.
The final photo of the museum mounted on the base/with sidewalk and cobblestone street.
Bob