One of those corridor runners passed the little party. They all had to squeeze back against the wall to let her pass. She wore black, but her robe was cut short to expose bare legs. She ran intently, eyes staring ahead, arms pumping, her long, spidery legs working; her upper chest was high, though her breasts were small, and she seemed to be breathing evenly. She ran on past them without breaking stride, and disappeared down the corridor, following its bend out of sight.

“Remarkable,” Nilis said, watching her go. “She looks as if she could run all day.”

“Perhaps she could,” Maruc said mildly. “That is her specialism.”

“Really? Well, well.” Nilis was playing the visiting dignitary, trying to put Maruc at ease, though without much success, Pirius thought.

They walked on. And behind them the strange young man with the data desks still trailed, unremarked.

Maruc opened a door and led them into a room. “A typical study area,” she said.

Brightly lit by light globes, the room contained desks and cubicles where people and bots, crammed in close together, worked side by side. Most of the scholars worked through flickering Virtual images, but some labored over data desks. The people were small, neat, their heads shaven like Maruc’s. Men and women alike were slim, and it was hard to distinguish between the sexes.

Some of those bare heads looked oddly large to Pirius, their skulls swollen and fragile. It was probably a trick of the light.

The visitors seemed to disturb these scholars. Some of them looked up, nervously, before cowering into their work, as if trying to hide. Others touched each other, clasping hands, rubbing foreheads, or even kissing softly. Not a word was spoken. Pirius could feel the tension in the room until he and the others receded again.

They walked on.

Maruc spoke of how the Archive had been digging its way into Mons Olympus for millennia. In many ways it was an ideal site for a library. Mars was a still, stable world, geologically speaking, and even this, its greatest mountain, had been dead for a billion years. The bulk of Olympus was basaltic rock, and under a surface layer smashed and broken by ancient impacts—in Maruc’s peculiar phrase, impact gardened—the rock was porous and friable, quite easy to tunnel into. It grew warmer the deeper you dug, Maruc said, but that wasn’t a problem; some of the deepest chambers even used Mars’s remnant inner heat as an energy supply. The tremendous shield of rock above was of course a protection from any deliberate aggression, as well as from natural disasters up to a small asteroid strike.

Pirius built up a picture of a great warren burrowed through the vast mound of Olympus, people everywhere, running along corridors and laboring in chambers. After twenty thousand years the Archive must run far, he thought, tens of kilometers, even hundreds: under Sol system’s greatest mountain, there was always more room.