Tunnels 01, Tunnels

the patter of falling water. He moved his head until just one eye was peering around the edge. He was struck dumb by what he glimpsed, and inched slowly into the open, into the bottle-green glow, to get a better view. From Tam's description, and the pictures his imagination had conjured up, he was expecting something out of the ordinary. But nothing could have prepared him for the sight that met his eyes.
    "The EternalCity," he whispered to himself as he began to move down a huge escarpment. As he looked up, his wide eyes scrutinizing the roof of the immense domed space, water splashed onto his upturned face and made him flinch.
    "Underground rain?" he muttered, immediately realizing how ridiculous that sounded. He blinked as it dripped into his eyes, stinging them.
    "It's seepage from above," Cal said, coming to a halt behind him.
    But Will wasn't listening. He was finding it hard to come to terms with the titanic volume of the cavern, so massive that its farthest reaches were hidden by fog and the mists of distance. The drizzle continued to fall in slow, languorous swathes as they set off again down the escarpment.
    It was almost too much to take in. Basaltic columns, like windowless skyscrapers, arced down from the mammoth span of the roof into the center of the city. Others speared upward from the outlying ground in mind-bending curves, encasing the city with gigantic undulating buttresses. It dwarfed any of the Colony's caverns with its scale, and brought to Will's mind the image of a gargantuan heart, its chambers crisscrossed by huge heartstringlike columns.
    He pocketed the light orb and instinctively sought the source of the emerald green glow that gave the scene a dreamlike quality. It was as though he were looking at a lost city in the depths of an ocean. He couldn't be sure, but the light seemed to be coming from the very walls themselves -- so subtly that at first he thought they were simply reflecting it.
    He crossed over to the side of the escarpment and examined the cavern wall more closely. It was covered in a wild growth of tendrils, dark and glistening with moisture. It was algae of some kind, made up of many trailing shoots and thickly layered, like ivy on an old wall. As he held up the palm of his hand, he could feel the warmth radiating from it and, yes, he could see that there was indeed a dim glow coming from the edges of the curled leaves.
    "Bioluminescence," he said aloud.
    "Mmmmmph?" came the vague response from under Cal's canvas hood, which was twitching absurdly from side to side as he kept watch for the Styx Division.
    As he continued down the incline, Will switched his attention back to the cavern, focusing on the most wondrous sight of all, the city itself. Even from this distance his eyes hungrily took in the archways, impossible terraces, and curving stone stairways sweeping up into stone balconies. Columns, Doric and Corinthian, sprang up to support dizzying galleries and walkways. His intense excitement was tinged with a sadness that Chester wasn't seeing all this with him as he should rightly have been. And as for Will's father, it would have blown his mind! It was just too much for him to absorb all at once. In every direction Will looked there were the most fantastic structures: collosseums and ancient domed cathedrals in beautifully crafted stone.
    Then, as he came to the bottom of the escarpment, the smell hit him. It had been deceptively gentle at first, like old pond water, but with each step they'd descended, the more pungent it had become. It was rancid, catching in Will's throat like a mouthful of bile. He cupped a hand over his nose and mouth and looked at Cal in desperation.
    "This is just gross!" he said, gagging on the stench. "No wonder you need to wear one of those things!"
    "I know," Cal said flatly, his expression hidden by the breathing mask as he pointed to the gully by the foot of the escarpment. "Come over here."
    "What for?" Will asked as he joined his brother. He was astonished to see him thrust his hands into the molasses-like slurry that lay stagnating there. Cal lifted out two handfuls of the black algae and rubbed it over his mask and his clothes. Then he grabbed Bartleby by the scruff of the neck. The cat let out a low howl and tried to get away, but Cal streaked him from head to tail. As the filth dripped over his naked skin, Bartleby arched his back and trembled, looking at his master balefully.
    "But the stink is worse that ever now! What the heck