A wide ascending tunnel bored into the earth behind the fortress, continuing in a straight line from the Great Arch's entry rampway. Indeed, this tunnel and the rampway were connected by a flat path that crossed the pillared hall and also featured raised gutters on its edges.

Zoe said, 'Looks like these gutters are designed to funnel some kind of liquid that flows out from the tunnel's core, through this hall, and down the front ramp.'

'No time to stop and stare,' West said. 'Keep moving.'

They ran across the stupendous hall, dwarfed by its immense pillars, and entered the gently-sloping tunnel sunk into its innermost wall.

At the same time, outside in the chasm, Big Ears, Stretch, Wizard and Pooh Bear were engaged in their fierce gunbattle with the CIEF force over in the other sentry tower.

'Keep firing!' Wizard yelled above the din. 'Every moment we keep Judah pinned down is another moment Huntsman has inside the Refuge-'

He was abruptly cut off as, all of a sudden, the entire chasm shook and shuddered.

For a moment, he and the others stopped firing.

So did Judah's men-in fact, they suddenly started to abandon their position on their sentry tower.

'What is this ...?' Big Ears eyed the cavern around him.

'It feels like an earthquake...' Pooh Bear said.

'It's not an earthquake,' Wizard said, realising.

The next instant, the source of the great rumbling burst out of the wall at the base of Judah's sentry tower, just above the waterline of the main chasm itself.

It was an M-113 TBV-MV (Tunnel-Boring Vehicle, Medium Volume). The military equivalent of a commercial tunnel-boring engine, it was in truth an M-113A2 bridge-laying vehicle that had been adapted for tunnel-making.

The size of a tank, it had a huge pointed nose that whizzed around and around, screw-like, obliterating everything in its path. Chewed-up rock and dirt were 'digested' through the centre of the vehicle and disposed out the rear. It also bore on its roof a foldable mechanical bridge.

The tunnel-boring vehicle poked out through the wall at the base of the sentry tower and stopped, its drill-bit still spinning, only twenty horizontal metres from the jetty that West had ziplined down to.

'They drilled through the filled-in excavation tunnel...' Wizard breathed in awe. 'How clever. It wouldn't have given a modern tunnel-borer much resistance.'

'It helps if you have the logistics,' Stretch said.

'Which they do,' Pooh Bear said.

At that moment, the tunnel-boring vehicle engaged its internal engines to fold forward the steel bridge on its roof. The mechanical bridge unfolded slowly, stretching out in front of the tunnel-borer until it was fully flat and extended. At which point, it touched down lightly against the jetty twenty metres away.

The American tunnel and the jetty were now connected.

'Man, they're good...' Big Ears said.

A second later, Judah's team rushed across the bridge, guns up, having raced down the internal stairs of their sentry tower.

They fired up at Wizard's men as they crossed the metal bridge.

Big Ears and the others tried to halt them with more cover fire, but it was no use.

Judah's men were across the waterway and racing up the rampway into Hamilcar's Refuge.

They were going in, only a minute behind West, Zoe and Lily.

West, Zoe and Lily raced up the ascending tunnel behind the fortress, guided by glowsticks.

As he ran, West noticed large clumps of dried solidified mud clinging to the edges of the rampway. He frowned inwardly. Dried mud? How had it come to be here? Dried mud? How had it come to be here?

'Jack! Zoe!' Wizard's voice called in their earpieces. 'Judah's crossed over the waterway! I repeat, Judah has crossed the waterway! He's right behind you!'

After about a hundred metres of dead-straight, steadily-rising tunnel, they emerged in a high dome-ceilinged chamber- -and froze.

'What the-' Zoe breathed. 'There are two two of them...' of them...'

The chamber was perfectly circular and it reeked of gaseous sulphur, the smell of volcanoes. It was also distinctly holy, reverential, a shrine.

Alcoves lined its curved walls-housing broken and decayed Carthaginian statues-while on the chamber's far side rose a wide granite dam, behind which simmered a wide pool of bubbling volcanic mud, the source of the foul sulphurous odour.

And lying on the floor before West, Lily and Zoe were six skeletons of long-dead n.a.z.i soldiers. All were hideously deformed: the bottom half of each man was missing, their legs simply gone. Indeed, the lower ends of their spinal columns seemed to have melted melted ... ...

Beyond the grisly skeletons, however, was the main feature of the holy chamber.

Rising up in the chamber's exact centre, 10 feet above the floor of the perfectly round room, was an elevated platform, fitted with a single flight of wide rising steps, and on it-to West's surprise- lay not one but two two Ancient Wonders. Ancient Wonders.

Mounted atop the island-like platform, aimed upwards like a satellite dish, stood the fabled Mirror of the Lighthouse of Alexandria.

It was completely covered in grey volcanic ash, but its outline was unmistakable. With its wide 15-foot dish, it was simply astonishing astonishing in its beauty. in its beauty.

West's eyes, however, fell immediately to its base.

Its solid trapezoidal base, also covered in a layer of grey ash.

Suddenly something made sense: the continual use of the word 'base' in the texts he had followed to get here. He recalled the original clue to the location of the Pharos Piece:

Look for the base that was once the peak of the Great Tower

And Euclid's Instructions:

Base removed before the Roman invasion, Taken to Hamilcar's Forgotten Refuge.

The Mirror of the Lighthouse was a wonder unto itself, but its base-its plain trapezoidal base-was of immensely greater value.

Its base was the Seventh Piece of the Golden Capstone.

But there was a second monument standing proudly atop the platform-next to the Mirror, on the right-hand side.

It was a huge octagonal marble pillar, standing upright, perhaps eight feet in height and seven feet in circ.u.mference. Its upper portions had long since been hacked away, but its lower section was perfectly intact.

And just like the Mirror, its base was trapezoidal.

It was another another Piece of the Capstone. Piece of the Capstone.

'Oversized octagonal pillar...' Zoe said, her mind racing. 'Only one ancient structure was known to possess oversized octagonal pillars-'

'The Mausoleum at Halicarna.s.sus,' West said. 'Lily hasn't been able to read its entry yet, but I bet when she does, the Callimachus Text will say that its Piece is with the Pharos Piece. When you find one, you find the other. Zoe, we just hit the jackpot. We just found two Pieces of the Capstone.'

'We have to do something!' Pooh Bear growled.

'What can can we do?' Stretch sighed. 'They're done for. This mission is over. I say we save ourselves.' we do?' Stretch sighed. 'They're done for. This mission is over. I say we save ourselves.'

They were still in their sentry tower, having watched Judah's force enter the Refuge.

'Typical of you, Israeli,' Pooh said. 'Your first instinct is always self-preservation. I don't give up so easily, or give up on my friends so easi-'

'Then what do you suggest, you stupid stubborn Arab?'

But Pooh Bear had gone silent.

He was staring out to the left of the fortress, out towards the high multi-arched aqueduct that spanned the channel on that side of the Y-junction.

'We cross that,' he said determinedly.

In the holy chamber, West approached the central island.

In addition to the two priceless treasures standing on it, one other thing was visible atop the raised island: a seventh n.a.z.i skeleton, lying all on its own, curled in the foetal position on the topmost step.

Unlike the others, this skeleton was not deformed in any way. It was whole and intact, still wearing its black SS uniform. Indeed, its bones were still covered in decaying flesh.

West approached the island and its flight of steps cautiously- the whole flight was probably just one great big trigger stone.

He scanned the skeleton.

Saw a pair of spindly wire-framed gla.s.ses still sitting on its nose, saw the red swastika armband, saw the purple amethyst ring on its bony right hand, the ring of a n.a.z.i Party founding member.

'Hessler...' he gasped in recognition. It was Hermann Hessler, the n.a.z.i archaeologist, one-half of the famed HesslerKoenig team.

Oddly, the skeleton's right hand was outstretched, seemingly reaching reaching down the steps, as if it had been Hessler's last earthly movement, grasping for... down the steps, as if it had been Hessler's last earthly movement, grasping for...

...a battered leatherbound notebook that lay on the bottom step.

West grabbed the notebook, flipped it open.

Pages of diagrams, lists, and drawings of each of the Ancient Wonders stared back at him, interspersed with German notes written in Hermann Hessler's neat handwriting.

Suddenly, his earpiece roared to life: 'Jack! Zoe!' Wizard's voice called. 'You have to hide! Judah's going to be there any moment now-'

West spun, just as a bullet sizzled out of the entry tunnel behind him and whizzed over his head, missing his scalp by centimetres.

'You two, that way!' he ordered Zoe and Lily to the left side of the doorway, while he himself scampered to the right of the stone doorframe, peered back, and saw dark shadows rising up the tunnel, approaching fast.

Decision time.

There was no way he could get to the podium containing the Lighthouse's Mirror and the Mausoleum's Pillar before Judah's force arrived. No way to allow Lily to glimpse their carved incantations.

His eyes scanned the chamber for an escape.

There was some open s.p.a.ce on the far side of the island, but it offered no escape: only the wide granite dam that held back the pool of superhot mud lay over there-presumably waiting to be set off by the trigger-stone steps.

And in an instant, it all made sense: the rising tunnel with the clumps of dried mud at its edges, the guttered path in the hall below and the similarly gutter-lined stairs down at the Great Arch: this molten mud, when released from its dam, would flow around around the raised island containing the Mirror and Pillar and then down through the Refuge, all the way to the water in the chasm, killing any crypt-raiders in the process and protecting the two Pieces. the raised island containing the Mirror and Pillar and then down through the Refuge, all the way to the water in the chasm, killing any crypt-raiders in the process and protecting the two Pieces.

The half-bodied n.a.z.i skeletons, melted at the waist, now also made sense: they'd been killed trying to outrun the mud. Hessler himself must have been trapped atop the podium as it had been surrounded by the stuff. He had then died in perhaps the worst way of all-of starvation, in the dark, alone. His buddy, Koenig, must have escaped somehow and trekked across the desert to Tobruk.

Among the many statue alcoves that lined the circular wall of the chamber, West also saw two smaller openings on either side of the main entry doorway.

They were low arched tunnels, maybe a metre high-and elevated slightly above the floor of the chamber by about 2 feet.

West didn't know what they were, and right now he didn't care.

'Zoe! That little tunnel! Get Lily out of here!'

Zoe swept Lily into the low arched tunnel on their side of the doorway, while West himself charged over to the right-hand one and peered down it.

The low tunnel disappeared downwards in a long dead-straight line.

'No choice,' he said aloud.

He ducked inside the little arched tunnel-just as Zoe and Lily did the same on the other side of the chamber-a bare second before Judah's force swept into the holy chamber.

At that exact same moment, four tiny figures were hustling across the superhigh aqueduct bridge that spanned the left arm of the Y-junction.