The new piste curved around the southern rim, crossing transversely some steep ridges and ravines which were called the Axius Valles. These corrugations ran from the rim’s rough hills down into the basin, forcing the piste viaduct to alternate between great arching bridges and deep cuts, or tunnels. The train they had boarded after the Zea Dorsa was a short private one belonging to the Odessa office, so Maya got it to stop at most of the small stations along this stretch, and she got out to meet and talk with the dowsing and construction crews. At one stop they were all Earthborn emigrants, and to Maya much more comprehensible than the blithe natives— normal-sized people, staggering around amazed and enthusiastic, or dismayed and complaining, in any case aware of how strange their enterprise was. They took Maya down a tunnel in a ridge, and it turned out that the ridge was a lava tunnel running down from Amphitrites Patera, its cylindrical cavity much the same size as Dorsa Brevia’s, but tilted at a sharp angle. The engineers were pumping the Amphitrites aquifer’s water into it, and using it as their pipeline to the basin floor. So now, as the grinning Earthborn hydrologists showed her as she stepped into an observation gallery cut into the side of the lava tube, black water was racing down the bottom of the huge tunnel, barely covering its bottom even at 200 cubic meters a second, the roar of its splashing echoing in the empty cylinder of basalt. “Isn’t it great?” the emigrants demanded, and Maya nodded, happy to be with people whose reactions she could understand. “Just like a damn big storm drain, isn’t it?”

But back at the train, the young natives nodded at Maya’s exclamations— lava tube pipeline, of course— very big, yes, it would be wouldn’t it— saved her some pipe for the less fortunate operations, yes? And then they went back to discussing some people they knew that Maya had never heard of.

• • •

As the train continued they rounded the southwest arc of the basin, and the piste led them north. They rode over four or five more big pipelines, snaking out of high canyons in the Hellespontus Montes to their left, canyons between bare serrated ridges of rock, like something out of Nevada or Afghanistan, the peaks whitened with snow. Out the windows to the right, down on the basin floor, there were more spreading patches of dirty broken ice, often marked by the flat white patches of newer spills. They were building on the hilltops by the piste, little tent towns like places out of the Tuscan Renaissance. “These foothills will be a popular place to live,” Maya said to Diana. “They’ll be between the mountains and the sea, and some of these canyon mouths should end up as little harbors.”

Diana nodded. “Nice sailing.”