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

What I need

He began his ascent, bubbles trailing behind as the dark shape faded from view. Reaching his boat, Eli sat in silence for a moment, his heart still racing from the strange encounter. He knew he needed better gear, more time, maybe even a high-definition camera. But mostly, he needed to know what was inside that building. It consumed his mind.