It was Ls 4, 2 March 22nd, M-year 32, and the southern days were getting shorter. Coyote drove their car hard every night, over intricate and invisible paths, through terrain that got more and more rugged the farther they got from the polar cap. They stopped to rest during the daylight, and drove the rest of the time. Nirgal tried to stay awake, but inevitably slept through part of every drive, and through part of every day’s stop as well, until he became thoroughly confused in both time and space.

      But when he was awake he was almost always looking out the window, at the ever-changing surface of Mars. He couldn’t get enough of it. In the layered terrain there was an infinite array of patterns, the stratified stacks of sand fluted by the wind until each winglike dune was cut like a bird’s wing. When the layered terrain finally ran out onto exposed bedrock, the laminate dunes became individual sand islands, scattered over a jumbled plain of outcroppings and clusters of rock. It was red rock everywhere he looked, rock sized from gravel to immense boulders that sat like buildings on the land. The sand islands were tucked into every dip and hollow in this rockscape, and they also clustered around the feet of big knots of boulders, and on the lee sides of low scarps, and in the interiors of craters.

      And there were craters everywhere. They first appeared as two bumps rolling over the skysill, which quickly proved to be the connected outer points of a low ridge. They passed scores of these flat-topped hills, some steep and sharp, others low and nearly buried, still others with their rims broken by smaller later impacts, so that one could see right in to the sand drifts filling them.

      One night just before dawn Coyote stopped the car.

      “Something wrong?”

      “No. We’ve reached Ray’s Lookout, and I want you to see it. Sun’ll be up in a half hour.”

      So they sat in the pilots’ seats and watched the dawn.

      “How old are you, boy?”

      “Seven.”

      “What’s that, thirteen Earth years? Fourteen?”

      “I guess.”

      “Wow. You’re already taller than me.”

      “Uh huh.” Nirgal refrained from pointing out that this did not imply any great height. “How old are you?”

      “One hundred and nine. Ah ha ha! You best shut your eyes or they’ll pop out of your head. Don’t you look at me like that. I was old the day I was born and I’ll be young the day I die.”

      They drowsed as the sky on the eastern skyline turned a deep purply blue. Coyote hummed a little tune to himself, sounding as if he had eaten a tab of omegendorph, as he often did in the evenings at Zygote. Gradually it became clear that the skysill was very far away, and also very high; Nirgal had never seen land so far away, and it seemed to curve around them as well, a black curving wall that lay an immense distance off, over a black rocky plain. “Hey Coyote!” he exclaimed. “What is this?”

      “Ha!” Coyote said, sounding deeply satisfied.

      The sky lightened and the sun suddenly cracked the upper edge of the distant wall, blasting Nirgal’s vision for a while. But as the sun rose, the shadows on the huge semi-circular cliff gave way in wedges of light that revealed sharp ragged embayments, scalloping the larger curve of the wall, which was so big that Nirgal simply gasped, his nose pressed right against the windshield—it was almost frightening it was so big! “Coyote, what is it?”

      Coyote let out one of his alarming laughs, the animal cackle filling the car. “So you see it isn’t such a small world after all, eh, boy? This is the floor of Promethei Basin. It’s an impact basin, one of the biggest on Mars, almost as big as Argyre, but it hit down here near the South Pole, so about half of its rim has since been buried under the polar cap and the layered terrain. The other half is this curved escarpment here.” He waved a hand expansively. “Kind of like a super-big caldera, but only half there, so you can drive right into it. This little rise is the best place I know for seeing it.” He called up a map of the region, and pointed. “We’re on the apron of this little crater here, Vt, and looking northwest. The cliff is Promethei Rupes, there. It’s about a kilometre high. Of course the Echus cliff is three kilometres high, and the Olympus Mons cliff is six kilometres high, do you hear that Mister Small Planet? But this baby will have to do for this morning.”

      The sun rose higher, illuminating the great curve of the cliff from above. It was deeply cut by ravines and smaller craters. “Prometheus Sanctuary is in the side of that big indentation there,” Coyote said, and pointed to the left side of the curve. “Crater Wj.”

      As they waited through the long day Nirgal looked at the gigantic cliff almost continuously, and each time it looked different, as the shadows shortened and shifted, revealing new features and obscuring others. It would have taken years of looking to see it all, and he found he could not overcome the feeling that the wall was unnaturally, or even impossibly huge. Coyote was right—the tight horizons had fooled him—he had not imagined the world could be so big.

      That night they drove into Crater Wj, one of the biggest embayments in the giant wall. And then they reached the curving cliff of Promethei Rupes. The cliff towered over them like the vertical side of the universe itself: the polar cap was nothing compared to this rock mass. Which meant that the Olympus Mons cliff that Coyote had mentioned would have to be … he didn’t know how to think it.

      Down at the foot of the cliff, at a spot where unbroken rock dropped almost vertically into flat sand, there was a recessed lock door. Inside was the sanctuary called Prometheus, a collection of wide chambers stacked like the rooms of a bamboo house, with incurving filtered windows overlooking Crater Wj and the larger basin beyond. The inhabitants of the sanctuary spoke French, and so did Coyote when talking to them. They were not as old as Coyote or the other issei, but they were pretty old, and of Terran height, which meant they mostly looked up to Nirgal, while speaking very hospitably to him, in fluent but accented English. “So you are Nirgal! Enchanté! We have heard of you, we are happy to meet you!”

      A group of them showed him around while Coyote did other things. Their sanctuary was very unlike Zygote; it was, to put it plainly, nothing but rooms. There were several large ones stacked by the wall, with smaller ones at the back of these. Three of the window rooms were greenhouses, and all the rooms throughout the refuge were kept very warm, and filled with plants