So she was not prepared for what she saw when they crested the second rise beyond the Wall. Since the Odinfolders lived in trees, there had been nothing that looked like a house or a shack or a shed or even a tent. But now they stood on the brow of a hill looking down into the valley of a swift-flowing river.
On the hither side of the river, there were only a few hundred hummocks with occasional walls, posts, and roofs rising out of them. Dust blowing primarily out of the east had drifted and turned everything into mounds of earth, covered in grass. Yet enough of the artifacts of human habitation still stood that it would have been an impressive, if bleak, sight.
But on the other side of the river, rising up to a flat mesa, the lower walls gave way to high towers. Most of them were skeletons now, with beams that marked the structure like bones, but many of them rose quite high, and because they had lost their façades, Param could see through each to the building behind, and the one behind that, and on and on up the slope.
On the flat of the butte, the great towers made way for somewhat lower, narrower buildings; but these, perhaps because they had sheltered each other from wind, still had much of their facing. They were ornately decorated and many still showed faded traces of once-bright colors. And the windows: a thousand eyes peered from every building.
Param was above two hundred when she gave up counting the towers.
“Ten thousand people must have lived here,” she said.
“Oh, no,” said Swims-in-the-Air. “This was a town of a million or so. And just down the river, you can see a city almost as big.”
It was true—though distance and bends in the valley made it so that nearby trees somewhat blocked the view, it was plain that about as many skeleton towers rose just as high, though starting on lower ground. The only thing missing was the patch of buildings with walls still in place.
“A million,” breathed Param. She knew the number as a theory, but had no idea what it would mean in practice. Aressa Sessamo was famous for having two hundred thousand inhabitants. Here, that would have been nothing. “How did they eat?”
“Food was easy,” said Mouse-Breeder. “We know how to make soil yield hundreds of times more than the primitive farms in Ramfold. It was energy and sewage that were a constant problem.”
“A million people would make it a pretty fecal city,” said Rigg. Umbo laughed.
Boys could be so crude. Param wondered how long it would be before they finally stopped finding ways to use “fecal” in every sentence. Olivenko didn’t think references to poo and pee were an inexhaustible source of mirth, the way Rigg and Umbo did.
“Where did they all go?” asked Param.
“Well, they died, of course,” said Swims-in-the-Air.
“Plague? War?” asked Param. “If food was easy, it wasn’t famine.” She had read enough history to know these were the ways that cities turned to ruins.
“No, not at all,” said Mouse-Breeder. “We weren’t so long-lived then. Only a hundred years, on average—once you’d seen your century, you expected your body’s functions to decay enough that living wasn’t a pleasure anymore. You lost interest. Or so I’m told.”
“We just hadn’t solved the problems of aging yet,” said Swims-in-the-Air.
“A hundred years is very, very old in Ramfold,” said Rigg.
“Yes, we’re so sorry, dear,” said Swims-in-the-Air.
“But that doesn’t explain anything,” said Param, a little impatient. “Just because people lived ‘only’ a hundred years doesn’t explain why the city emptied out like this.”
“The first time through our history,” said Mouse-Breeder, “our population reached six billion by the time the humans came.”
“You say that as if we weren’t human ourselves,” said Olivenko.
Swims-in-the-Air only smiled. “We do, don’t we,” she said.
“Again,” said Param, “I don’t see why the cities—”
“This one likes quick answers,” said Mouse-Breeder.
“Or easy ones,” said Swims-in-the-Air. “So here’s the quick and easy answer. We got a letter from the future, telling us how the world ends. So we set about trying to make it end differently. Each attempt meant cutting our population more sharply, until you see us as we are today, about ten thousand people in the entire wallfold, and most of us clustered within walking distance of the Wall.”
“Cutting your population?” asked Param. “How?”
“Having fewer babies, of course. Most of us having none at all. That’s why my two children became part of my name.”
“She’s such an optimist,” said Mouse-Breeder.
“Incurable,” said Swims-in-the-Air. But she sounded wistful and sad when she said it.