Crystalline Cavern

Bored out by clans of Steelix centuries ago and cut ever-larger by the wide river that has since filled it, this massive tunnel runs from near Era Castle under the entire length of the West to the ocean, and is rumored to have once been a secret escape route for royalty. Strange crystals along the riverbed and sparsely across the walls emit a dull light, making the cavern whimsical, but ceasing to glow if removed. Due to these factors, it is popular for all manners of romantic, commercial, and illegal activities, while its sheer size and many crevices branching off from the river path keep it seclusive.