This mod adds large underworlds to Minetest. Each is an open horizontal plane with different characteristics. The underzones table in init.lua contains all the data on each plane, including how far underground to generate it.
There are five default underworlds: Caina (ice realm), Phlegethos (fire and lava), Dis (city of hot iron and brass), Minauros (decay and pollution), and Styx (vast ocean).
The source is available on github.
Mod dependencies: default
Download: https://github.com/duane-r/underworlds/ ... master.zip