Perhaps the most glorious monuments of the civilization of the Incas were the public or royal roads, extending from the capital to the remotest parts of the empire. Their remains are still most impressive, both from their extent and the amount of labor necessarily involved in their construction, and in contemplating them we know not which to admire most--the scope of their projectors, the power and constancy of the Incas who carried them to a completion, or the patience of the people who constructed them under all the obstacles resulting from the topography of the country and from imperfect means of execution. They built these roads in deserts, among moving sands reflecting the fierce rays of a tropical sun; they broke down rocks, graded precipices, levelled hills, and filled up valleys without the assistance of powder or of instruments of iron; they crossed lakes, marshes, and rivers, and without the aid of the compass followed direct courses in forests of eternal shade. They did, in short, what even now, with all of modern knowledge and means of action, would be worthy of the most powerful nations of the globe. One of the principal of these roads extended from Cuzco to the sea, and the other, which is followed to La Paz, ran along the crest of the Cordilleras from one end of the empire to the other, their aggregate lengths, with their branches, being about four thousand miles. Modern travellers compare them, in respect of structure, to the best works of the kind in any part of the world. In ascending mountains too steep to admit of grading, broad steps were cut in the solid rocks, while the ravines and hollows were filled with heavy embankments, flanked with parapets, and planted with shade-trees and fragrant shrubs. They were from eighteen to twenty-five Castilian feet broad, and were paved with immense blocks of [Illustration: CHASQUIS AT REST.]