...and it only took me twenty-two years...

Here's a rough animation (the transitions are a bit naff)...

@Mike-Amos Because.

Here's a hi-res Video of a more complete model (added the verdigris flashing)...

BTW, how do you delete or edit individual replies..???

Well, I always told myself I didn't need to model the original building's stairwell... but I couldn't resist... First try using PBR materials: it's all looking a bit dark. I wonder when SU will support light sources..? I cannot get rid of the depth fighting at the top of the stairs....