The Lava Lakes, falls and zones is are biomes you can only get to by going through the Lost rivers. It is a key feture of subnautica. In it is The Prison, with a very old Sea Emperor Leviathan trapped inside. It has 3 Sea Dragon Leviathans, millions of rockgrubs, a group of lava larva, a reaper leviathan skeleton, a ion making thingy, kyanite, the recipies for ion machienery, a pit, a hoarde of artifacts and 5 sonic deturrent devices. Fun place, super easy to get lost in, and looks RAD.
