Why these curves were made, I never ascertained, although afterward I gave the subject much attention. We started down the aqueduct at a brisk pace, our candles being frequently extinguished by fresh drafts of air, that struck us at almost every turn. Whenever they occurred, we paused a moment, to reillume them, and then hastened on, as silently and swiftly as before. After traversing at least five or six miles of this passage, occasionally passing arched chambers like that at the foot of the staircase, we suddenly reached the termination of the aqueduct, which was an apartment the _fac-simile_ of the one at the other end of it. Here also we observed a stone stairway, and my companion at once began the ascent. During our journey through the long arched way behind us, we frequently passed through rents, made possibly by earthquakes, and more than once were compelled to crawl through openings half filled with rubbish, sand and stones. Nor was the road dry in all places. Indeed, generally, the floor was wet, and twice we forded small brooks that ran directly across the path. Behind us, and before, we could distinctly hear the water dripping from the ceiling, and long before we reached the end of the passage, our clothing had been completely saturated. It was, therefore, with great and necessary caution, that I followed my guide up the slippery stairs. Our ascent was not so tedious as our descent had been, nor was the distance apparently more than half so great to the surface. Pio paused a moment at the head of the stairway, extinguished his candle, and then requested me by a gesture to do likewise. When this was accomplished, he touched a spring and the trap-door flew open, _upwards_. The next instant I found myself standing in a chamber but dimly lighted from above. We soon emerged into open daylight, and there, for the first time since the conquest of Mexico by Cortes, the eyes of a white man rested upon the gigantic ruins of _La Casa Grande_. These ruins are far more extensive than any yet explored by travelers in Central America. Hitherto, they have entirely escaped observation. The natives of the country are not even aware of their existence, and it will be many years before they are visited by the curious. But here they were, a solid reality! Frowning on the surrounding gloom of the forest, and the shadows of approaching night, they stretched out on every side, like the bodies of dead giants slain in battle with the Titans.