Blacksite: “JOTUN” Entrance

Board

A cave which houses a most curious structure within. It is as though a sealed tomb, but it has walls of smooth metal, strangely shaped stones which have faces that glimmer and shine with shifting lights and words, torches that do not flicker or burn… There is a scrawl along the wall, written in bolded script: “PROJECT: JOTUN”…
What is this place you have come across?

The Entrance to a long-sealed Blacksite from the ancient 4,000-year past, before the great cataclysm that changed the world. Will the characters who come across it leave it be for another to find? Or will they attempt to plumb the depths to see what fascinating things may be found?

Using Jayco‘s Wolf Cave as a starting point:
https://talestavern.com/slab/wolf-cave-3/