Avram Bronski said, 'This may be the most luxurious prison cell in the solar system.'

They were in a four-room apartment cut out of the rock high up on one side of the immense cave. The walls were panelled with a light reddish-brown wood-like material. The ceiling was stone but painted with murals depicting scenes of domestic animals. No 'Martians' appeared in them nor were they represented in the framed paintings on the walls. These paintings were either abstract art, still life, or of buildings or creatures that either existed there or were from mythology. Some looked like dragons; one was a whalelike seven-horned beast bursting out of a sea.

Bronski, who had been doing some private speculating, had explained that the law against representing any living creature in painting, sculpture, or in any form whatsoever, had been modified. But he thought, if he were right, that it was still forbidden to make images of sentient beings.

'Though not in holographic communication,' he said. 'And, since their medical science seems to be highly advanced, they must use pictures of the human body in textbooks and replicas of organs and so forth for the students. I don't have the slightest idea whether or not they dissect corpses.'

The holographic TV sets in the apartment could be dialled to see and hear the correct time. After three days' confinement, Orme and Bronski had learned to read the numbers necessary to understand the system. Bronski, who on Earth was a famed linguist in addition to being a premier areologist, had mastered the words associated with the symbols. They had correlated their own chronometers to the local time. But they didn't think they'd be going any place soon, so time was of no special concern.

One of the few things they'd ascertained was that the tau and the omega on the tunnel door were not of Greek origin. That language was spoken by a few here, but the arithmetical symbols on the TV sets came from a place far from Earth.

Orme got up off the chair and walked to Bronski. Together they stared at a scene that had become familiar by now, though it hadn't lost its fascination. Their prison was about one hundred feet up on one wall of the vast hemisphere cut out of solid basalt. The base of the wall opposite was an estimated thirty-five miles away. The apex of the dome seemed to be a mile and a half high.

From where they stood, they could see seven enormous horseshoe-shaped openings and twenty-one smaller ones. These must lead to passageways opening into other hollows. They believed that this hollow was only part of a gigantic underground complex.

Except for the floor of the dome, the stone was sky-blue. This was not the natural colour of basalt, so it must have been spray-painted or treated with something else. Whatever the method used, the dome looked just like the heavens above Earth on a cloudless day.

About one hundred feet below the highest point of the hemisphere hung a sun-bright globe. A half-hour before 18:00 in the 'evening', it began to dim. By 18:00 it was shining feebly, as if the sun had turned into the moon. This was the only light aside from that coming from the windows of houses, until 06:00, when the 'sun' began to wax.

The luminary didn't seem to be hanging from a cable though it was difficult to see past the brightness. But if it was suspended without attachment, it was held up by some sort of antigravity device. Until now Orme and Bronski had been sure that antigravity machines were possible only in science fiction; that is, unless you labelled stairs, ladders, elevators, balloons, airships, airplanes, and rockets as such.

So far, the luminary was the only thing they'd seen without visible means of support. The people they saw either walked or rode horses or horse-driven buggies and wagons or bicycles or the few wheeled-powered vehicles.

The cavern floor was neither level nor curving downward to form a horizon. Instead, it had a gentle gradient upward from the centre in all directions, ending at the wall. Water flowed from holes at the base of the wall and formed winding brooks, creeks, and two rivers. The latter were each about three-quarters of a mile wide. The smaller streams flowed into the rivers, which emptied eventually into a roughly hourglass-shaped lake in the centre. This was half a mile wide at the broadest parts and two miles long.

There were trees and farms and small parks and forests everywhere with villages here and there. The only structures over two storeys high were the barns. Each obviously residential structure was surrounded by a large yard and had a garden. Some of the buildings looked like schools. To each village was attached an open stadium where track and field meets, horse races, and games were held. One of the games was much like soccer and another was a form of basketball. There were also many public swimming pools, but no private house had any.

Through the binoculars given them by Hfathon, one of their captors, they could see much of what would otherwise have been blurred or unviewable. If there were tall buildings anywhere, they would have been able to detect them. The upward swell of the floor assured that.

Two-lane paved roads connected the towns and farms. They saw no trucks, though horse-drawn wagons laden with farm produce were plentiful.

Near the central lake was a long one-storey building into which people streamed in large numbers at 08:00. They left at noon and picnicked in parks or swam or boated in the lake. An hour later they re-entered; at 14:00 they swarmed out. Most went to houses within a range of a mile, but others bicycled or rode horses or even jogged to more distant dwellings.

Bronski thought that it might be the main administration building for the government.

'There's no telling how many levels there are under the ground.'

Opposite this, on the other side of the lake, was what had to be a university campus. Other buildings, from the number of people who entered them on the Sabbath, looked like places of worship.

All the structures were roofed. Orme wondered why they should be, since the entire hollow was probably air-conditioned. The fourth day, he found out why. Water rained from the ceiling of the dome for half an hour.

'So that's why the farms don't have irrigation systems.'

The captives had eaten their noon lunch, and then put the dirty dishes on trays into a wall-slot. Now they watched Martians driving up in two automobiles towards them. These disappeared below the porch, and presently the heads of those in the first vehicle appeared. There was a road leading up alongside the prison. But these people seemed to prefer walking to driving whenever possible.

So far, Orme and Bronski had no complaints about ill-treatment. They had been given thorough physical and medical examinations and had been interrogated, but they were well-housed, well-fed, and given plenty of privacy.

The six Martians paused while the shatterproof glass front of the room rose into a slot overhead. Orme knew that the transparent stuff was unbreakable because he had tested it with various chairs, his booted foot, and a heavy bronze vase.

Three of their captors were Homo sapiens, very tall, well-built, and wearing flowing robes. Two of these had long dark hair and full beards and were dark-skinned. The third had light skin, dark-blue eyes, and a golden-brown beard. All wore long curly sidelocks.

The other trio were humanoid, but a glance showed a Terrestrial that they came from another planet. They were almost seven feet tall, no unusual height for Terrans in 2015 AD. This, their slimness, their long arms and legs, and their quickness would have qualified them for the best basketball team on Earth. They had five long-nailed fingers and toes and aside from their faces resembled humans closely. Their skins were a light bronze; their eyes, almost purplish; their hair was feathery. One was yellow; one, Titian; one, black. Both the female and the two males had hairless faces. Whether it was because they just lacked hair or because they shaved, the Earthmen did not yet know. Like their human companions, they sported long curling earlocks.