I’ve been working on this for about two months now, here’s a comparison of early on vs later:
The vegetation is hand-painted:
Everything else was done entirely in Blender.
The smoke and clouds were rendered separately and composited in for quick editing.
Lots of geometry nodes here- the cobwebs, swallow’s nests, stairs, path, and fences were all created with geonodes.
The clouds were also created with geometry nodes:
The compositing nodetree has over 50 nodes, it’s quite complex. Here’s an earlier version of it:
I’m using extremely dense geometry to allow for highly detailed procedural distortion using geometry nodes:
The whole scene, not counting everything that’s still geonodes, weighs in at 7m triangles.
On meshes where materials share a line boundary, I’ve also used geometry nodes to artistically distort that boundary.
I’m quite proud of my swallow nest generator:
You can download and play around with that generator:
swallownest.blend (124.3 KB)
This is my largest project ever, literally speaking- the project folder is 121 GB.
I had quite a few other camera angles, but due to the time challenge of hand-painting vegetation, I decided not to move forward with these. You can see some of them below:
Some miscellaneous progress shots:
Lastly, this is the reference image that inspired it all (it’s a still from a Studio Ghibli movie, not sure which one):
You can read about this in more detail here:
You may notice that details about the shaders are quite sparse- I’ve been working on perfecting this look for some time, and I’m not really comfortable sharing information about it on the open internet. Feel free to DM me and I can share more.
Thanks for looking 
I think it turned out pretty well also
