Now, from all the hovering air-boats came the thrumming of the sound-rays, directed at the temple and the city, from all the scores of cars that hung above that city. The ground beneath pitched, heaved up torturedly, and then the city collapsed, sank down with a thundering, ear-splitting roar into the great pit that lay beneath, the earth over the cavern being shattered by the disintegrating vibrations of the sound-rays. All the city, with the great temple below us, crashed down, and vanished in a mighty cloud of dust. The dust hung, cleared, disappeared. And beneath lay nothing but a great depression in the earth, a vast, raw bowl in the earth's surface, with here and there a white fragment showing in the brown earth. Under that huge sunken bowl, I well knew, lay the city of the cylinders, with its Kanlars and soulless slaves, and under it, too, lay the city of the pit, and the people of the pit, the thousands of fierce warriors who had pressed us up the stair so savagely, seeking to carry destruction and death down to a peaceful city. Standing there on Kethra's car, we surveyed the scene in silence. And there was silence all around us, for from all the massed cars came no word or shout, the men on them gazing down into the torn depression below as though loth to believe that their victory was won at last, the evil menace of the Raider crushed forever. So we looked, there in the hushed silence. In the east, the sun was rising higher ... higher.... _CHAPTER 18_ EIGHT MINUTES! It was hours later, toward the end of the hot, brilliant afternoon, that we parted at last from Kethra and his men. On the green earth around that brown pit where once had stood the city of cylinders, the Khlun air-boats were resting, ready for their long flight homeward across the ice. Our own time-car lay behind us, for in that tense moment before the city had collapsed under the sound-rays' vibrations, a hovering air-boat had spied our car in the little glade where we had left it, and had managed to raise it from the ground before the crash. And now, with our four friends, we stood beside it, bidding Kethra farewell. We had heard from him the story, as amazing as our own, of what had befallen his forces when they pursued the Raider into the future, how they had chased him almost to the world's end, indeed, pursuing him into time so far that the sun grew old and small, and the world a world of death and twilight; of how they had forced the Raider to desert the Kanlar cars it held, which they had destroyed; and of how it had eluded them in time and come racing back to confront us on the temple's roof. He told, too, of how the messenger sent through time by Lantin and me had finally found him and brought him back in the nick of time to destroy Raider, hordes and city.