Closer we came and closer, while I watched spellbound; now we were at its head, and the litter-bearers swept upon it. All of five hundred feet wide it was, surface smooth as a city road, sides low walled, curving inward as though in the jetting-out of its making the edges of the plastic rock had curled.

On and on we sped; the high thrusting precipices upon which the bridge’s far end rested, frowned close; the enigmatic, dully shining dome loomed ever greater. Now we had reached that end; were passing over a smooth plaza whose level floor was enclosed, save for a rift in front of us, by the fanged tops of the black cliffs.

From this rift stretched another span, half a mile long, perhaps, widening at its centre into a broad platform, continuing straight to two massive gates set within the face of the second cliff wall like panels, and of the same dull gold as the dome rising high beyond. And this smaller arch leaped a pit, an abyss, of which the outer precipices were the rim holding back from the pit the red flood.