Desire and curiosity raged within us like a calenture; and we gave no heed to the hazards and travails of exploration. Over us stood the eternal azure of vacant heavens, matching in their desolation the empty landscape. The route steepened; and above us now was a wilderness of cragged and chasmed rock, where nothing dwelt but the sinister wide-winged condors.

Often we lost sight of certain eminent peaks that had served us for landmarks. But it seemed that our guide knew the way, as if led by an instinct more subtle than memory or intelligence; and at no time did he hesitate. At intervals we came to the broken fragments of a paved road that had formerly traversed the whole of this rugged region: broad, cyclopean flags of gneiss, channeled as if by the storms of cycles older than human history. And in some of the deeper chasms we saw the eroded piers of great bridges that had spanned them in other time. These ruins reassured us; for in the primordial volume there was mention of a highway and of mighty bridges, leading to the fabulous city.

Polder and I were exultant; and yet I think that we both shivered with a curious terror when we tried to read certain inscriptions that were still deeply engraved on the worn stones. No living man, though erudite in all the tongues of Earth, could have deciphered those characters; and perhaps it was their very alienage that frightened us. We had sought diligently during many laborious years for all that transcends the dead level of mortality through age or remoteness or strangeness; we had longed ardently for the esoteric and bizarre: but such longing was not incompatible with fear and repulsion. Better than those who had walked always in the common paths, we knew the perils that might attend our exorbitant and solitary researches.

Often we had debated, with variously fantastic conjectures, the enigma of the mountain-builded city. But, toward our journey’s end, when the vestiges of that pristine people multiplied around us, we fell into long periods of silence, sharing the taciturnity of our stolid guide. Thoughts came to us that were overly strange for utterance; the chill of elder aeons entered our hearts from the ruins—and did not depart.

We toiled on between the desolate rocks and the sterile heavens, breathing an air that became thin and painful to the lungs, as if with some admixture of cosmic ether. At high noon we reached an open pass, and saw before and above us, at the end of a long and vertiginous perspective, the city that had been described as an unnamed ruin in a volume antedating all other known books.

The place was built on an inner peak of the range, surrounded by snowless summits little sterner and loftier than itself. On one side the peak fell in a thousand-foot precipice from the overhanging ramparts; on another, it was terraced with wild cliffs; but the third side, facing toward us, was a steep acclivity with broken-down scarps and chimneys that would offer small difficulty to expert mountaineers. The rock of the whole mountain was strangely ruinous and black; but the city walls, though gapped and worn to a like dilapidation, were conspicuous above it at a distance of leagues.

Polder and I beheld the bourn of our world-wide search with thoughts and emotions which we did not voice. The Indian made no comment, pointing impassively toward the far summit with its crown of ruins. We hurried on, wishing to complete our journey by daylight; and, after plunging into an abysmal valley, we began at mid-afternoon the ascent of the slope toward the city.

We were impressed anew by the abnormal blackness and manifold cleavages of the rock. It was like climbing amid the overthrown and fire-blasted blocks of a Titan citadel. Everywhere the slope was rent into huge, obliquely angled masses, often partly vitrified, which made the ascent a more arduous problem than we had expected. Plainly, at some former time, it had been subjected to the action of intense heat; and yet there were no volcanic craters amid the nearby mountains. Puzzling greatly, I recalled a passage in that old volume, hinting ambiguously at the dark fate that long ago destroyed the city’s inhabitants: “For the people of that city had reared its walls and towers too high amid the region of the clouds; and the clouds came down in their anger and smote the city with dreadful fires; and thereafter the place was peopled no more by those primal giants who had built it, but had only the clouds for inhabitants and custodians.” But from this passage I could still draw no definite conclusion: for the ideation was too fantastic to be understood as anything more than a dubious figure of speech.

We had left our three llamas at the slope’s bottom, merely taking with us provisions for a night. Thus unhampered, we made fair progress in spite of the ever-varying obstacles offered by the shattered scarps. After a while we came to the hewn steps of a stairway mounting toward the summit; but the steps had been wrought for the feet of colossi, and, in many places, they were part of the heaved and tilted ruin; so they did not greatly facilitate our climbing.

The sun was still high above the western pass behind us; and for this reason, as we went on, I was much surprised by a sudden deepening of the char-like blackness on the rocks. Turning, I saw that several greyish vapory masses, which might have been either clouds or smoke, were drifting idly about the summits that overlooked the pass; and one of these masses, rearing like a limbless figure, upright and colossal, had interposed itself between us and the sun.

Sebastian and the guide had also noted this phenomenon. Clouds were almost unheard-of amid those arid mountains in summer; and the presence of smoke would have been equally hard to explain. Moreover, the grey masses were wholly detached from each other and showed a peculiar opacity and sharpness of outline. At second glance they did not really resemble any cloud-forms we had ever seen; for about them there was a baffling suggestion of weight and solidity. Moving sluggishly into the heavens above the pass, they preserved their original contours and their separateness. They seemed to swell and tower, coming toward us on the blue air from which, as yet, no lightest stirring of wind had reached us. Floating thus, they maintained the rectitude of massive columns or of giants marching on a broad plain.

I think we all felt an alarm that was none the less urgent for its vagueness. Somehow, from that instant, it seemed that we were penned up by unknown powers and were cut off from all possibility of retreat. All at once, the dim legends of the ancient volume had assumed a menacing reality. We had ventured into a place of hidden peril—and the peril was upon us. In the movement of the clouds there was something alert, deliberate and implacable. Polder spoke with a sort of horror in his voice, uttering the thought which had already occurred to me:

“They are the sentinels who guard this region—and they have espied us!”

We heard a harsh cry from the Indian. Following his gaze, we saw that several of the unnatural cloud-shapes had appeared on the summit toward which we were climbing, above the megalithic ruins. Some arose half hidden by the walls, as if from behind a breastwork; others stood, as it were, on the topmost towers and battlements, bulking in portentous menace, like the cumuli of a thunder-storm.

Then, with terrifying swiftness, many more of the cloud-presences towered simultaneously from the four quarters, emerging from behind the gaunt peaks or assuming sudden visibility in mid-air. With equal and effortless speed, as if convoked by an unheard command, they gathered in converging lines upon the eyrie-like ruins. We the climbers, and the whole slope about us and the valley below, were plunged in a twilight weird and awesome as that of central eclipse.

The air was still windless, but it weighed upon us as if burdened with the wings of a thousand cacodemons. I remembered that I was conscious of our exposed position, for we had paused on a wide landing of the mountain-hewn steps. We could have concealed ourselves amid the huge fragments on the surrounding slope; but, for the nonce, we were incapable of the simplest movement. The rarity of the air had left us weak and gasping. And the chill of altitude crept into us.