At once Hurus Hol led the way directly down the street toward the heart of the city, and as we hastened on beside him he answered to my question, "We must get to the city's center. There's something there which I glimpsed from our ship, and if it's what I think----" He had broken into a run, now, and as we raced together down the bare length of the great, shining avenue, I, for one, had an unreassuring presentiment of what would happen should the huge buildings around us disgorge their occupants before we could get out of the city. Then Hurus Hol had suddenly stopped short, and at a motion from him we shrank swiftly behind the corner of a pyramid's slanting walls. Across the street ahead of us were passing a half-dozen of the tentacle-creatures, gliding smoothly toward the open door of one of the great pyramids. A moment we crouched, holding our breath, and then the things had passed inside the building and the door had slid shut behind them. At once we leapt out and hastened on. We were approaching the heart of the city, I judged, and ahead the broad, shining street we followed seemed to end in a great open space of some sort. As we sped toward it, between the towering luminous lines of buildings, a faint droning sound came to our ears from ahead, waxing louder as we hastened on. The clear space ahead was looming larger, nearer, now, and then as we raced past the last great building on the street's length we burst suddenly into view of the opening ahead and stepped, staring dumfoundedly toward it. It was no open plaza or square, but a pit--a shallow, circular pit not more than a hundred feet in depth but all of a mile in diameter, and we stood at the rim or edge of it. The floor was smooth and flat, and upon that floor there lay a grouped mass of hundreds of half-globes or hemispheres, each fifty feet in diameter, which were resting upon their flat bases with their curving sides uppermost. Each of these hemispheres was shining with light, but it was very different light from the feeble glow of the buildings and streets around us, an intensely brilliant blue radiance which was all but blinding to our eyes. From these massed, radiant hemispheres came the loud droning we had heard, and now we saw, at the pit's farther edge, a cylindrical little room or structure of metal which was supported several hundred feet above the pit's floor by a single slender shaft of smooth round metal, like a great bird-cage. And toward this cage-structure Hurus Hol was pointing now, his eyes flashing. "It's the switch-board of the thing!" he cried. "And these brilliant hemispheres--the unheard-of space-path of this dark star--it's all clear now! All----" He broke off, suddenly, as Nal Jak sprang back, uttering a cry and pointing upward. For the moment we had forgotten the hovering cones above the city, and now one of them was slanting swiftly downward, straight toward us.