Fisherman Finds Giant Rusted Chain, Then Locals Warn Him Not To Touch It

A massive ship

Then their lights caught it—the sharp curve of a massive bow jutting from the darkness. Luke froze, air hissing loudly through his regulator. A ship, impossibly preserved, stood half-buried in the cavern. Its masts bent awkwardly against the stone ceiling, its hull still whole. The chain ran straight to it, vanishing into its side. Luke whispered, “How is this even possible?”