Slowly but surely the portal opened. Wider and wider it swung, until there burst on the astonished gaze of the travelers a flood of light. The sun was shining overhead, though fast declining in the west, but in the bright glare of the slanting beams there was revealed the underground city.

There it stood in all its ancient splendor, most of it, however, but mere ruins of what had been fine buildings. There were rows and rows of houses, stone palaces and what had been beautiful temples. Nearly all of the structures showed traces of elaborate carvings.

But ruin was on every side. The roofs of houses, temples and palaces had fallen in. Walls were crumbling and the streets were filled with debris. As the boys looked, some foxes scampered among the ruins, and shortly afterward a jaguar slunk along, crawling into a hole in a temple wall.

“Grand! Beautiful! Solemn!” exclaimed the professor, in raptures over the discovery. “It is more than I dared to hope for. Think of it, boys! We have at last discovered the buried city of ancient Mexico. How the people back in civilization will open their eyes when they hear this news! My name and yours as well will be covered with glory. Oh, it is marvelous!”

“I guess it will be some time before the people back in Cresville hear of this,” observed Jerry. “There doesn’t seem to be any way of sending a letter from here. I don’t see any telegraph station, and there’s not a messenger boy in sight.”

“That’s funny,” said Ned. “You’d think a buried city, a dead one, so to speak, would be just the place where a district messenger would like to come to rest.”

“It’s a lonesome place here,” remarked Bob. “I hope we’ll find some one to talk to.”

“That’s just the beauty of the place,” said the professor. “What good would an ancient, ruined, buried city be if people were living in it? I hope there isn’t a soul here but ourselves.”

“I guess you’ll get your desire, all right,” remarked Jerry.