A mountain-chain, pierced through from base to summit—a gorge four miles in length, walled in by lofty precipices; between their dizzy heights the giant stream of the Old World, the Danube.        Did the pressure of this mass of water force a passage for itself, or was the rock riven by subterranean fire? Did Neptune or Vulcan, or both together, execute this supernatural work, which the iron-clad hand of man scarce can emulate in these days of competition with divine achievements?        Of the rule of the one deity traces are visible on the heights of Fruska Gora in the fossil sea-shells strewn around, and in Veterani's cave with its petrified relics of saurian monsters of the deep; of the other god, the basalt of Piatra Detonata bears witness. While the man of the iron hand is revealed by long galleries hewn in the rock, a vaulted road, the ruined piers of an immense bridge, the tablets sculptured in bas-relief on the face of the cliff, and by a channel two hundred feet wide, hollowed in the bed of the river, through which the largest ships may pass.        The Iron Gate has a history of two thousand years. Four nations—Romans, Turks, Roumanians and Hungarians, have each in turn given it a different name.