Nothing in Ancient Peru was more remarkable than the public roads. No ancient people has left traces of works more astonishing than these, so vast was their extent, and so great the skill and labor required to construct them. One of these roads ran along the mountains through the whole length of the empire, from Quito to Chili. Another, starting from this at Cuzco, went down to the coast and extended northward to the equator. These roads were built on beds or “deep under-structures” of masonry. The width of the roadways varied from twenty to twenty-five feet, and they were made level and smooth by paving, and in some places by a sort of macadamizing with pulverized stone mixed with lime and bituminous cement. This cement was used in all the masonry. On each side of the roadway was “a very strong wall more than a fathom in thickness.” These roads went over marshes, rivers, and great chasms of the sierras, and through rocky precipices and mountain sides. The great road passing along the mountains was a marvelous work. In many places its way was cut through rock for leagues. Great ravines were filled up with solid masonry. Rivers were crossed by means of a curious kind of suspension bridges, and no obstruction was encountered which the builders did not overcome. The builders of our Pacific Railroad, with their superior engineering skill and mechanical appliances, might reasonably shrink from the cost and the difficulties of such a work as this. Extending from one degree north of Quito to Cuzco, and from Cuzco to Chili, it was quite as long as the two Pacific railroads, and its wild route among the mountains was far more difficult. Sarmiento, describing it, said, “It seems to me that if the emperor (Charles V.) should see fit to order the construction of another road like that which leads from Quito to Cuzco, or that which from Cuzco goes toward Chili, I certainly think he would not be able to make it, with all his power.” Humboldt examined some of the remains of this road, and described as follows a portion of it seen in a pass of the Andes, between Mansi and Loxa: “Our eyes rested continually on superb remains of a paved road of the Incas. The roadway, paved with well-cut, dark porphyritic stone, was twenty feet wide, and rested on deep foundations. This road was marvelous. None of the Roman roads I have seen in Italy, in the South of France, or in Spain, appeared to me more imposing than this work of the ancient Peruvians.” He saw remains of several other shorter roads which were built in the same way, some of them between Loxa and the River Amazon. Along these roads at equal distances were edifices, a kind of caravanseras, built of hewn stone, for the accommodation of travelers.