I was once making a map that was based on Dante's Inferno. You started out above ground and quickly decended into a hell type atmosphere. It looked VERY similar to what you are doing in these pics. But I gave up eventually since I hit bedrock and still needed to add so much more.
It was really cool though... I had completed the first 3 areas featuring a network of hand made caves twisting around and through a massive waterfall. This led to a large hallway that ended with a blind drop off. You then landed in a small lake that was part of the grotto type area leading you to a boat for navigting down the river styx. I was working on creating a labyrinth at the end of the river but that is where I gave up.
I wish I still had that map, somehow I lost it.
Wow, the similarities between your map and what I'm doing, are very uncanny. I'm also going for that kind of map, although I'm referencing more than one religion and picking a couple of different things from various myths and fiction. A map based on Dante's Inferno is a really cool concept, and it's a shame you couldn't complete it. Hopefully, when we collaborate on this map you can also provide some input.
At this point, I may need a couple of people to mould this map together because I really just want to see this become a reality. I'm working on a story with characters with dialogue atm. Anyone following this thread should be aware, that spoilers could jump out at you at any time, so you've been warned; I may start sharing more of the storyboard and plot in the coming days/weeks.
Also thought of using Styx but going with Acheron, and so will need to create Charon ;)
Honestly, I'm still surprised with the similarities. I hope to implement different features into this map, including puzzles, parkour, plot etc, although the way I'm going about it atm, I may be building up too much hype... Fingers crossed it doesn't turn out like No Man's Sky.