Diver Finds Structure on Ocean Floor — Then Finds Out Why It’s There

Uneasy realisation

To the left of the platform, he found a series of stacked stones forming a narrow, doorless passage. He slipped inside, passing between walls so close his shoulders nearly touched them. The stone was different here—darker, more porous. This realization made Eli feel uneasy. It made him realize that he was down here as well, and if anything collapsed, he was surely trapped forever, or worse.