The main screen being on, the whole crew saw it. Someone shouted and they stopped to stare, and Steffens was about to call for altitude when he saw that the city was dead. He looked down on splintered walls that were like cloudy glass pieces rising above a plain, rising in a shattered circle. Near the center of the city, there was a huge, charred hole at least three miles in diameter and very deep. In all the piled rubble, nothing moved. Steffens went down low to make sure, then brought the ship around and headed out across the main continent into the bright area of the sun. The rocks rolled by below, there was no vegetation at all, and then there were more cities--all with the black depression, the circular stamp that blotted away and fused the buildings into nothing. No one on the ship had anything to say. None had ever seen a war, for there had not been war on Earth or near it for more than three hundred years. The ship circled around to the dark side of the planet. When they were down below a mile, the radiation counters began to react. It became apparent, from the dials, that there could be nothing alive. After a while Ball said: "Well, which do you figure? Did our friends from the fourth planet do this, or were they the same people as these?" Steffens did not take his eyes from the screen. They were coming around to the daylight side. "We'll go down and look for the answer," he said. "Break out the radiation suits." He paused, thinking. If the ones on the fourth planet were alien to this world, they were from outer space, could not have come from one of the other planets here. They had starships and were warlike. Then, thousands of years ago. He began to realize how important it really was that Ball's question be answered. When the ship had gone very low, looking for a landing site, Steffens was still by the screen. It was Steffens, then, who saw the thing move. Down far below, it had been a still black shadow, and then it moved. Steffens froze. And he knew, even at that distance, that it was a robot. Tiny and black, a mass of hanging arms and legs, the thing went gliding down the slope of a hill. Steffens saw it clearly for a full second, saw the dull ball of its head tilt upward as the ship came over, and then the hill was past. * * * * * Quickly Steffens called for height. The ship bucked beneath him and blasted straight up; some of the crew went crashing to the deck. Steffens remained by the screen, increasing the magnification as the ship drew away. And he saw another, then two, then a black gliding group, all matched with bunches of hanging arms. Nothing alive but robots, he thought, _robots_. He adjusted to full close up as quickly as he could and the picture focused on the screen. Behind him he heard a crewman grunt in amazement.