Flying above a broad, but rapid and turbulent stream, the fleet soon neared a large city, and the visitors from Earth gazed with interest at this metropolis of the unknown world. The buildings were all the same height, flat-roofed, and arranged in squares very much as our cities are arranged. There were no streets, the spaces between the buildings being park-like areas, evidently laid out for recreation, amusement, and sport. There was no need for streets; all traffic was in the air. The air seemed full of flying vehicles, darting in all directions, but it was soon evident that there was exact order in the apparent confusion, each class of vessel and each direction of traffic having its own level. Eagerly the three men studied the craft, which ranged in size from one-man helicopters, little more than single chairs flying about in the air, up to tremendous multiplane freighters, capable of carrying thousands of tons. Flying high over the city to avoid its congested air-lanes, the fleet descended toward an immense building just outside the city proper, and all landed upon its roof save the flagship, which led the Skylark to a landing-dock nearby--a massive pile of metal and stone, upon which Nalboon and his retinue stood to welcome the guests. After Seaton had anchored the vessel immovably by means of the attractor, the party disembarked, Seaton remarking with a grin: "Don't be surprised at anything I do, folks. I'm a walking storehouse of junk of all kinds, so that if occasion arises I can put on a real exhibition." As they turned toward their host, a soldier, in his eagerness to see the strangers, jostled another. Without a word two keen swords flew from their scabbards and a duel to the death ensued. The visitors stared in amazement, but no one else paid any attention to the combat, which was soon over; the victor turning away from the body of his opponent and resuming his place without creating a ripple of interest. Nalboon led the way into an elevator, which dropped rapidly to the ground-floor level. Massive gates were thrown open, and through ranks of people prostrate upon their faces the party went out into the palace grounds of the Domak, or Emperor, of the great nation of Mardonale.