They had no idea how deep it was before they quit descending. It felt like the belly of the whale.
They did not know the history of man's meanderings underground, the lore of his tentative exploration. They hadn't entered this Bosnian maw for love of caving. These were normal enough men in normal enough times, none obsessed with climbing the highest mountain or soloing an ocean. Not one saw himself as a Columbus or a Balboa or a Magellan or a Cook or a Galileo, discovering new lands, new pathways, a new planet. They didn't mean to go where they went. And yet they opened this hadal door. After two days in the strange winding corridor, Branch's platoon reached its limit. They grew afraid. For where the tunnels forked for the hundredth time and plunged still lower, they came upon a footprint. And it was not exactly human. Someone took a Polaroid photo and then they di-di maued it back to the surface.
The footprint in that GI's Polaroid photo entered the special state of paranoia
usually reserved for nuclear accidents and other military slips. It was designated a Black Op. The National Security Council convened. The next morning, NATO commanders met near Brussels. In top secrecy, the armed forces of ten countries poised to explore the rest of Branch's nightmare.
Branch stood before the council of generals. 'I don't know what they were,' he said, once more describing his night of the crash in Bosnia. 'But they were feeding on the dead, and they were not like us.'
The generals passed around the photo of that animal track. It showed a bare foot, wide and flat, with the big toe separate, like a thumb. 'Are those horns growing on your head, Major?' one asked.
'The doctors call them osteophytes.' Branch fingered his skull. He could have been the bastard child of an accidental mating between species. 'They started coming back when we went down.'
There was, the generals finally accepted, more to this than just a coal hole in the Balkans. Suddenly, Branch found himself being treated not like damaged goods, but like an accidental prophet. He was magically restored to his command and given free rein to go wherever his senses led him. His eight troops became eight hundred. Soon other armies joined in. The eight hundred became eighty thousand, then more. Beginning with the coal mines at Zulu Four, NATO recon patrols went deeper and wider and began to piece together a whole network of tunnels thousands of meters below Europe. Every path connected another, however intricately. Enter Italy and you might exit in Slovakia or Spain or Macedonia or southern France. But there was no mistaking a more central direction to the system. The caves and pathways and sinkholes all led down.
Secrecy remained tight. There were injuries, to be sure, and a few fatalities. But the casualties were all caused by roofs collapsing or ropes breaking or soldiers tripping into holes: occupational hazards and human error. Every learning curve has its price. The secret held, even after a civilian cave diver by the name of Harrigan penetrated a limestone sinkhole called Jacob's Well in south Texas, which supposedly transected the Edwards Aquifer. He claimed to have found a series of feeder passages at a depth of minus five thousand feet, which went deeper still. Further, he swore the walls contained paintings by Mayan or Aztec hands. A mile deep! The media picked it up, checked around, and promptly cast it aside as either a hoax or narcosis. A day after the Texan was made a fool in public, he disappeared. Locals reckoned the embarrassment had been too much for him. In fact, Harrigan had just been shanghaied by the SEALs, handed a juicy consultant's fee, sworn to national secrecy, and put to work unraveling sub-America.
The hunt was on. Once the psychological barrier of 'minus-five' was broken – that magical five-thousand-foot level that intimidated cavers the way eight thousand meters once did Himalayan mountaineers – the progress plunged quickly. One of Branch's long-range patrols of Army Rangers hit minus-seven within a week after Harrigan went public. By month five, the military penetration had logged a harrowing minus-fifteen. The underworld was ubiquitous and surprisingly accessible. Every continent harbored systems. Every city.
The armies fanned deeper, acquiring a vast and complex sub-geography beneath the iron mines of West Cumberland in South Wales and the Holloch in Switzerland and Epos Chasm in Greece and the Picos Mountains in Basque country and the coal pits in Kentucky and the cenotes of Yucatàn and the diamond mines in South Africa and dozens of other places. The northern hemisphere was exceptionally rich in limestone, which fused at lower levels into warm marble and beerstone and eventually, much deeper, into basalt. This bedrock was so heavy it underlay the entire surface world. Because man had rarely burrowed into it – a few exploratory probes for petroleum and the long-abandoned Moho project – geologists had always assumed that basalt
was a solid compressed mass. What man now found was a planetary labyrinth. Geological capillaries stretched for thousands of miles. It was rumored they might even reach out beneath the oceans.
Nine months passed. Every day the armies pushed their collective knowledge a little further, a little deeper. The Army Corps of Engineers and the Seabees saw their budgets soar. They were tasked to reinforce tunnels, devise new transport systems, drill shafts, build elevators, bore channels, and erect whole camps underground. They even paved parking lots – three thousand feet beneath the surface. Roadways were constructed through the mouths of caves. Tanks and Humvees and deuce-and-a-half trucks pouring ordnance, troops, and supplies into the inner earth.
By the hundreds, international patrols descended into the earth's recesses for more than half a year. Boot camps shifted their theater training. Jarheads sat through films from the United Mine Workers about basic techniques for shoring walls and maintaining a carbide lamp. Drill instructors began taking recruits to the rifle ranges at midnight for point-and-fire practice and blindfolded rappels. Physician assistants and medics learned about Weill's disease and histoplasmosis, fungal infections of the lungs contracted from bat guano, and Mulu foot, a tropical cave disease. None were told what practical use any of this had. Then one day they would find themselves shipped into the womb.