Cuzco is the oldest city in South America. Once the capital of the Incan Empire, it has always been one of the most developed cities in the ancient world. Just outside of Cuzco lie the ruins of Sacsahuaman built as a fortress to help protect the capital from attack. The entrance is marked by a massive megalithic gateway and astounding gray-blue walls. Here the ancient builders constructed three great terraces, which extend one above another for a third of a mile across the hill between two deep gulches. The lowest terrace of the fortress is faced with colossal boulders, many of which weigh ten tons and some weigh more than twenty tons, yet all are fitted together with the utmost precision.

About a mile northeast of Sacsahuaman are several small artificial hills, partly covered with vegetation, which seem to be composed entirely of gray-blue rock chips—chips from the great limestone blocks quarried here for the fortress and later conveyed with the utmost pains down to Sacsahuaman. They represent the labor of countless thousands of quarrymen. Even in modern times, with power drills, explosives, steel tools, and light railways, these hills would be noteworthy, but when one pauses to consider that none of these mechanical devices were known to the ancient stonemasons and that these mountains of stone chips were made with stone tools and were all carried from the quarries by hand, it fairly staggers the imagination.

The ruins of Sacsahuaman represent not only an incredible amount of human labor, but also a very remarkable governmental organization. That thousands of people could have been spared from agricultural pursuits for so long a time as was necessary to extract the blocks from the quarries, hew them to the required shapes, transport them several miles over rough country, and bond them together in such an intricate manner, means that the leaders had the brains and ability to organize and arrange the affairs of a very large population. Such a folk could hardly have spent much time in drilling or preparing for warfare. Their building operations required infinite pains, endless time, and devoted skill. Such qualities could hardly have been called forth, even by powerful monarchs, had not the results been pleasing to the great majority of their people, people who were primarily agriculturists. They had learned to avert hunger and famine by relying on carefully built, stone-faced terraces, which would prevent their fields being carried off and spread over the plains of the Amazon.

Such a display of the power to control the labor of thousands of individuals and force them to superhuman efforts on an unproductive undertaking, which in its agricultural or strategic results was out of all proportion to the obvious cost, might have been caused by the supreme vanity of a great soldier. On the other hand, the ancient Peruvians were religious rather than warlike, more inclined to worship the sun than to fight great battles. Was Sacsahuaman due to the desire to please, at whatever cost, the god that fructified the crops which grew on terraces? It is not surprising that the Spanish conquerors, warriors themselves and descendants of twenty generations of a fighting race, accustomed as they were to the salients of European fortresses, should have looked upon Sacsahuaman as a fortress. To them the military use of its bastions was perfectly obvious. The value of its salients and reëntrant angles was not likely to be overlooked, for it had been only recently acquired by their crusading ancestors. The height and strength of its powerful walls enabled it to be of the greatest service to the soldiers of that day. They saw that it was virtually impregnable for any artillery with which they were familiar. In fact, in the wars of the Incas and those which followed Pizarro's entry into Cuzco, Sacsahuaman was repeatedly used as a fortress.

So it probably never occurred to the Spaniards that the Peruvians, who knew nothing of explosive powder or the use of artillery, did not construct Sacsahuaman in order to withstand such a siege as the fortresses of Europe were only too familiar with. So natural did it seem to the first Europeans who saw it to regard it as a fortress that it has seldom been thought of in any other way. The fact that the sacred city of Cuzco was more likely to be attacked by invaders coming up the valley, or even over the gentle slopes from the west, or through the pass from the north which for centuries has been used as part of the main highway of the central Andes, never seems to have troubled writers who regarded Sacsahuaman essentially as a fortress. It may be that Sacsahuaman was once used as a place where the votaries of the sun gathered at the end of the rainy season to celebrate the vernal equinox, and at the summer solstice to pray for the sun's return from his “farthest north.” In any case I believe that the enormous cost of its construction shows that it was probably intended for religious rather than military purposes. It is more likely to have been an ancient shrine than a mighty fortress.