the water, and it’ll stay good as new. We’re in fresh water down to about fifteen metres, when you hit salt water.”
Jack looked up at the thin shaft of light streaming in from the ceiling above, to the ugly face he could just make out peering down at them. The rope and sling that had been used to winch them down had now been pulled up again, to await their return. He thought of Maria, and took a deep breath from his rebreather. He gave an okay signal to Costas. “Right. Let’s get going.” They dumped air from their wings and dropped beneath the surface, Jack following Costas just above the current. It was cooler than the sea, justifying their full wetsuits, but refreshing after the torrid heat above. They both wore triple headlamps on their helmets, and the beams revealed an awesome scene as they panned them around. Stalagmites reared up from the base of the cave in clusters, overlying caves and grottoes. The water was crystal clear, as clear as Jack had ever seen, flickering with pastel colours. They dropped down and rode the back of the current, their arms outstretched and their fins extended behind to keep them stable. Seconds later they swept under an overhang into a dark tunnel, leaving the gloomy light of the entrance chamber behind.
“When it’s not raining, this tunnel’s partly above water,” Costas said. “You can see the waterline on the walls beside us, with fresh calcium formations above it. It looks like there’d normally be enough space for a small canoe or raft.”
Costas took out a pencil-size lightstick, cracked it to mix the chemicals and then dropped it into a fissure. Jack watched the green glow disappear behind him, and Costas took out half a dozen more. “I’m assuming we’ll want to come back this way,” he said. “The current’s weak near the ceiling, so it shouldn’t be a problem.”
Jack rolled over and saw a canopy of rock with none of the telltale ripples from air pockets. They had come at least two hundred metres from the entrance, maybe more. “Any guesses how much farther?” he said.
“I reckon we’re looking for another chamber, somewhere accessible from the entrance chamber. If this tunnel dips below the waterline, we’re on the wrong track.” As Costas spoke, the passageway began to do exactly the opposite, rising up and opening out, and their beams reflected off the underside of a water pool that spread out above them as far as they could see. “Hey presto.”
They surfaced and looked around, awestruck. They were inside another huge cavern, at least fifty metres across, extending in a great dome that reached up to the jungle floor. It was how Jack imagined the sacred cenote at Chichen Itza had once looked, before the limestone ceiling collapsed. Unlike the entrance chamber, this one was pitch dark, with no visible opening to the surface. They swam slowly across the pool, their lights reflecting off fantastic shapes that dazzled them like sculptures in ice. Stalagmites rose out of the depths like sub-sea volcanic vents, some of them joining stalactites to form continuous columns like the pillars of some great cathedral. They could see the force of nature still at work, rainwater seeping through the limestone ceiling and spattering on the exposed formations, adding another sheen of minerals in a process that had begun thousands of years before human history first touched this place.
In the centre was an island, one that seemed to have been created entirely from calcium accretion. The surface was a bizarre array of shapes which looked like some fantasy citadel. Huge tendrils hung down over it from high above, the fossilised roots of long-dead trees.
As the slope up to the island became visible, Costas dropped down to the bottom, about eight metres below. Suddenly he seemed to be swimming sideways, and Jack saw him grab a stalagmite and pull himself up the slope until the current had released him and he could swim free again.
“That was frightening.” Costas stopped about five metres below Jack, and was catching his breath. “You’d never be able to swim against that. Take a look to your right and you can see where it goes.”
Jack peered across to a point directly opposite the entrance tunnel. He could see a shimmering disturbance where the underwater river swept through the chamber, exiting under an overhang near the base of the cavern about twenty metres away. It was a black hole, a forbidding place with no sign of natural light farther on. Jack realized how close he had come to losing Costas. He closed his eyes and swore to himself. As so often in diving it was the casual decision, the deceptively benign conditions, that nearly had fatal consequences. Jack had not given a second’s thought to Costas’ decision to drop down, yet the danger was as great as any they had faced in the iceberg, or back in the tunnels of Atlantis. And in cave diving there was rarely a second chance, no going back on a wrong move.
“Jack, I’ve found something.” Costas was a little farther upslope, but his upper body was wedged in a fissure. Jack sank down beside him, keeping a wary eye on the current a few metres away. Costas emerged in a cloud of silt and pressed an object at Jack. “Get a hold of that.”
It was a human jawbone. A small one, a child’s. It was brown with age, but perfectly preserved. Costas held the rest of the skull towards him, and Jack could see the eye sockets, the lines where the bones of the cranium had not yet fused. “They’re everywhere,” Costas said. “Hundreds of them.” Jack looked around. Lying in the silt, piled at the base of stalagmites, grimacing out from under overhangs: skulls, limb bones, ribs. He reached into the silt and pulled out a small jade pendant, shaped like the gaping jaw of some mythical beast, like the image of the underworld on the wall painting in the temple. He glanced through the translucent waters at the dark hole where the river disappeared, and felt a sudden chill of certainty.
“Human sacrifice,” he said. “The Toltecs must have lowered themselves and their victims through the hole in the ceiling just as we were, then paddled through into this chamber. This was the edge of their underworld, the closest they could get. When the current was strong, after a storm, they could have thrown their victims into the very maw of the underworld, watched them sucked into that black hole and out of earthly existence. This must have been the ultimate place of sacrifice.”
“We don’t seem to be able to get away from that,” Costas muttered. “I’m beginning to yearn for Vikings again.”
“You may just be in luck.”
“What do you mean?”
“Upslope, about three metres. At the edge of the island.”
It was another skull, larger than the others, with different wear on the teeth. It had been badly crushed, as if the victim had suffered a terrific blow to the face. But it was not the skull that had excited Jack’s interest. It was what it was wearing.
A gilded metal helmet, cone-shaped, with a long nose-guard.
Jack’s heart began to race. He wafted the bottom, raising clouds of silt. Maya pots, intact. More human bones. A shining disc, gold, covered with glyphs. A handle protruding from a gully, covered in gilt wire. A sword handle. Beside it a long wooden haft, a glint of metal at the end.
With mounting excitement Jack drew himself out of the water, Costas beside him. Both men quickly doffed their rebreathers and fins and stashed them on the edge. With their helmets removed they could hear the noise of the cavern, water dripping on the pool, the whoosh of bat wings, eerie sounds magnified and distorted by echo. They clambered up on to a level platform and surveyed the underground island. It was about ten metres in diameter, rising to a cone in the middle, covered in slick accretion. The centre was a gigantic single stalagmite, growing from the cavern floor beneath the ceiling where the fall of leached calcium had been greatest. Around it were stalagmites that had formed more recently as the shape of the ceiling had changed, some of them beneath the calcified tree roots which hung over them in a fantastic shroud.
Jack was carrying a torch, and he swept the beam over the island before placing his hand on the stalagmite nearest to them. It was a peculiar shape, almost seeming to curve above them, on the face of it no more extraordinary than anything else they were seeing around them.
“My God.” Jack’s voice was resonant, echoing.
“What is it?”
Jack stumbled back a few steps, then shone his torch up the stalagmite. He remembered what Jeremy had suggested when they had last spoken. His voice was taut with amazement. “Remember our longship in the ice?”
Costas followed his gaze, puzzled, and then gasped. The top of the stalagmite was a bulbous shape that extended out from the curve. They were looking at the prow of a Viking ship, the details of its surface lost under a millennium of accretion but the shape unmistakable. It was an astonishing sight.
“They must have carried it with them from the longship,” Jack murmured. “Erected it here, a last battle standard.” He shone the torch at the bulbous form on top. “The Eagle.”
“Look on either side,” Costas exclaimed. “I could be wrong, but I think it’s a shield wall.”
