Minecraft Cathedral

See also: http://pdurdin.deviantart.com/art/Minecraft-Cathedral-189498747

To use it follow these steps (from memory):

1. Download the world file: https://drive.google.com/file/d/1JvhWPxnbcFfxrgwkATewFzHP2YFLTPru/view?usp=drive_link

2. Locate your Minecraft world data folder.

3. Back up any existing "World3" folder you may have to another location (you might be able to rename things, I dunno).

4. Put the zipped World3 folder in its place.

5. Run Minecraft and load World 3.

I think that's how it works. :)

PS. I recommend Peaceful mode to avoid monsters under the floor... :D