19
Jack hit the water with a resounding splash, the echo resonating off the walls of the cavern. Costas had preceded him and was already carrying out an underwater recce, the arc of light from his headlamp visible off to one side. Jack quickly released the carabiner on the rope and gave it a tug. The rope began to jerk upwards, and Jack followed the glint of metal from the carabiner as it rose up the thin shaft of light to the hole in the limestone ceiling almost twenty metres above. He and Costas had silently kitted up in the ancient chamber a few minutes before, donning the equipment Reksnys had ordered them to bring from Seaquest II. Jack had refused to divulge any of his thoughts about the wall-painting, and Maria had remained obstinately silent in the corner of the chamber even after the tape had been ripped away from her mouth.
Jack was convinced that the scene with the menorah showed the Well of Sacrifice at Chichen Itza, not this place. Yet all the indications were that Reksnys was right to think that the tunnel ahead of them held some clue to Harald Hardrada’s last stand. The location of the temple above the cavern, the depiction of the jungle battle with the river running beneath it, local Maya tradition.
There had been no chance to make contact with the security team, who had been on standby since he and Costas had left in the Zodiac two hours before. Jack knew the Lynx was in the air somewhere offshore, but Ben could do nothing until Jack and Costas found some way of radioing in their co-ordinates and confirming that the situation with Maria was safe enough for an intervention. Jack had given Maria a reassuring look just before he donned his helmet, had been cool and collected as Loki had winched him down the hole. But his mind was in a tumult at the prospect of what might lie ahead, desperately running through the possibilities if they were to return empty-handed. At the moment the options were few, and they were not good.
Costas’ voice came through the intercom. “There’s an underground river running through the bottom of this chamber, about eight metres beneath you. The current’s pretty vicious. Not exactly recommended cave diving conditions.”
“Roger that,” Jack replied, floating on the surface and following the sweep of light below that marked Costas’ progress. He tested his buoyancy compensator and ran a systems check on the computer that controlled his gas supply. They were wearing semi-closed circuit rebreathers, variable mixed-gas systems that enabled them to go to greater depths than either pure oxygen or air would allow. It was a precaution, as they had no expectation that the cave system would exceed the thirty-metre maximum typical of the Yucatan cenotes.
“Remind me about this calcium carbonate stuff,” Jack said.
Costas surfaced beside him, inflating the buoyancy wings on his backpack and adjusting the intercom on his helmet. “Dissolved limestone,” he said. “During the Ice Age, everything here was above water. That’s when the stalagmites and stalactites that are now underwater formed. Then at the end of the Ice Age, the sea level rose and the caves flooded. Leave something above water in one of these caverns, and it’ll get encased in stone. Drop it in 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.