"Naturally they thought I was delirious," Regan said, "or had been. They had to accept the fact that I'd been through the Earth. Not through the center of it, or anywhere near it--they tell me that's practically solid nickel, or molten, or whatever. But there was no disputing that I'd gone down in the Atlantic and come up in the Indian Ocean. They'd seen me go down and they'd seen me come up and obviously I'd been somewhere in the interval. I hadn't walked, that was for sure. "They credited my story of the underground river. The Greeks had a word for it, they tell me. The Greeks thought the Alpheus River wandered down under the Adriatic and came up in Sicily. I don't know much about their river, but mine apparently follows the Earth's curve maybe a dozen miles below the surface. "But nobody wanted any part of my story of the city and the king and the beehive houses and the rectangular bus. Delirium, they said. Oh, they were kind about it, but they said it. So did the geophysical boys upstairs, in their eight-syllabled way." The bartender brought fresh highballs, but Regan still held the glass the old drink had been in. He put it on its side on the bar and stared at the open end. I got the image--a tunnel filled with rushing water, a tunnel under the world. Regan almost echoed my thoughts. "Tunnel under the Antarctic," he said half to himself. "That's where it must have been, that city. Down there, deep under the ice. Used to be tropics, you know." "The Antarctic?" I said. "Before the ice came, before the Earth's axis shifted. Those people--they didn't evacuate, I guess. They went underground. Funny they should have built themselves houses the same shape as those of the Eskimos who stayed above-ground in the North--like igloos. But probably that's just coincidence. You don't find igloos in the tropics. I'd guess their beehive houses are naturally influenced by the cavern they live in--their little universe." * * * * * Regan looked up. He grinned and set the empty glass upright on the bar. "I've had a lot of time to think about it. They're awfully nice people, all of them. I could have had a wonderful time if I'd been able to climb out of that damn spacesuit. In time, I could even have communicated with them passably well. Good-looking women, too." He looked at me speculatively. He opened his mouth as if to speak again, then smiled and shook his head. I said it for him: "You're going back." "Yes," he answered. "Yes, I'm going back. I know the coordinates of the entrance to the passageway and its dimensions and the kind of equipment I'll need. Nothing elaborate. In another year or so, I'll have enough saved up, I think. Get myself a little space launch; one of the smaller ones, lifeboat size. Fit it out with food and water--and some picture books, of course, to show them what it's like where I come from. I'd take somebody along with me if I could find anyone who wanted to go--and who believed me."