They marched on, descending another few hundred feet as they went. Around them, they could now hear the shifting and cracking of rock as though they were moving along some deep fault line, and the heat and humidity became more unbearable with every step they took.

Matt laid his hand on the rock wall. “This is impossible. The earliest traces of modern man arrived here about thirty thousand years ago. But this system looks as old as anything in Egypt or Troy – this shouldn’t be here.”

“So who built it?” Abrams was shining his light deeper along the tunnel.

“I think we’re about to find out.” With his hand, Matt traced some more symbols in the stone. An image flashed into his mind of a dark sea, so still that it could have been black ice, except for the vapors hanging over its warm surface. Without knowing, he had the feeling it was fathomless, but that still, down in that inky liquid, something watched and waited. Something far older than humankind, or anything else that ever lived on the planet.

“We’re going the right way,” he said.

“How do you know?” Abrams asked, turning and shining his light back at Matt’s feet so as not to ruin his night vision.

Matt stared off into the dark, wondering that himself. “I don’t know how I know, I just know.”

“Well, might have been nice to make the announcement before we split up.” Abrams looked at his watch. “Two more minutes.” He turned and moved quickly along the edge of the wall, with Matt following. A hint of breeze sprang up, and in another minute, it seemed to increase.

“Something up ahead, I think.” Abrams started to pick up the pace, and then in the next moment, he stopped dead, his arms pinwheeling in the air.

Matt lunged forward and grabbed him by the collar, holding on – the man’s toes were already over the edge of a cliff. He dragged him back, the major falling onto his ass.

“Jesus Christ.” Abrams got to his feet, and leaned up against the wall.

The path had simply ended, and their tunnel had opened out into a larger cavern. The size was unknown, as their lights couldn’t find either the other side, the roof or, coming to the edge again, the bottom.

“Wow.” Matt put a hand over his face. Wafting up from somewhere deep down in the blackness was a foul breeze that once again reminded him of dead fish and bloated drying bodies on a beach.

“A fucking cliff.” Abrams was still shaken, but he came forward and peered over the edge. “Hey, thanks, Matt. I knew you’d come in handy.” He straightened. “I guess this is as far as we go.”

Matt shook his head. “Look over there.”

Starting beside them, and then set in along the wall, was a wide pathway carved directly into the stone. It circled along and downward, spiraling along the outside of the enormous vacant space, until it disappeared in the dark. The path crossed over in front of other darkened tunnels just like their own, each with the same strange alien shape that Matt had earlier noticed.