“What causes the fireworks?” Steve asked above the noise. “Partly strong wind,” Bobby said loudly, “and partly Titan’s gases exploding against the mountain tops!” They watched spellbound for fifteen minutes, then a half hour. The Shannons were sure they had never seen anything quite so breathtaking as this. At one time a row of peaks seemed to glow with a sheet of red flame. The flame danced and flickered like a forest fire for a long time before it faded out. The children had been enjoying themselves so thoroughly that they knew nothing of the peril that was heading their way. The first warning came when one of the skyport men standing nearby shouted over his space suit radio. Steve whirled in alarm. His heart seemed to stop beating completely for a terrible moment. A tardy plane had come in for a landing on the sky platform. But the howling wind had kept everyone from hearing the warning siren. Because of the fierce blowing, the plane had not hooked firmly to the braking line. It scooted off to the side and was heading for the very spot where Bobby, Steve and Sue stood. “Bobby!” Steve cried. “Get out of the way!” As Bobby ducked for safety, Steve also moved quickly. Sue screamed as Bobby grabbed her hastily by her space glove. He had to jerk her sharply in order to get her out of the path of the runaway plane. The plane crashed into the plastic wall of the skyport, tearing out a section of wall as though it were thin cardboard. The ship was left dangling on the very edge as if ready to fall a mile to the ground. “The poor pilot!” Sue cried. “Oh, I can’t look!” But the skyport men had come running quickly over and together they pulled the jet plane back to safety. They helped the scared pilot out. He walked shakily off into one of the hangars. “Whew! That was close!” Steve breathed. “For him and us, too!” “My heart is still thumping like a drum!” Bobby said. As for Sue, she was too upset to say anything at all. They turned to look at the fireworks to take their minds off the accident. The wonderful ending of the show almost made them forget it completely. They saw a dazzling white light burst like an empty volcano. The banner of fire rose as high into the sky as huge Saturn. Then it spilled over like a great fountain. It changed into purple, then blue, green and red. Before dying out, it gave the big planet a lovely ruddy glow, showing up its rings like a gleaming necklace of rubies. That was the end of Nature’s grand performance. “Wow, wasn’t that terrific?” Steve asked. “A show like that in a grandstand on Earth would cost you three-and-a-half.” “Maybe four!” Sue chimed in. “You can’t see this show anywhere on Earth, Steve,” Bobby said. “Titan is the only place. And the good thing about it is that it’s all for free!” _ADVENTURE ON THE SUN’S DOORSTEP_