There was no money or other medium of exchange; gold and silver were used only for purposes of adornment; such trade as there was, was by barter. Every man was obliged to work for the common good at some form of industry or occupation suitable to his strength and age and, if able, to take his turn at the maintenance and extension of the irrigation systems, which in that way were brought to such a state of perfection that modern Peru still lives on the half-ruined fragments of their canals and conduits and reservoirs. Hardly a spot of arable soil was left uncultivated. Whole mountains were terraced for thousands of feet up their sides. Private ownership in land did not exist; it belonged to the communes. The custom was to divide it into tracts, each large enough to support a family, and parcel it out; for every child born there was an additional allotment, and, at intervals, a general revision and redistribution. The produce was divided into three parts: one for the Inca and his establishment, one for the priesthood, and one for the commune. When one section of the country was impoverished by war or some other casualty, its needs were supplied by assessments levied on the others. The occupations of the women, both in town and country, were essentially domestic. Some were brought up from childhood and specially educated to serve in the religious rites and in the household of the reigning Inca. These were known as Virgins of the Sun. The capital, Cuzco, was located in a valley about two hundred miles northwest of Lake Titicaca and at a lower elevation, yet still more than two miles up above the level of the sea. A colossal, massive-walled citadel loomed over it from the heights of Sacsahuaman above the town. Strong walls and towers inclosed it on every side. In its midst was a great square, from which started the remarkable roads leading to the four corners of the empire, referred to by Hawthorne. One whole side was occupied by the temple, and near by were the dwellings of the priests and the palaces of the Inca and the Virgins of the Sun. This sacred space was a citadel in itself, protected by five heavy walls.