Another new nether structure, this cathedral comes with a labyrinth underneath, have fun getting through it, as with my new builds this one ties in with the new nether updates.
I did not do much with the interior as I really don't want to limit the overall creative designs that are possible with a structure this size, there are some shots of what I have done in my test world, but overall I left it up to you to fill the interior as best suits your needs.

Enjoy.