One of those colonies, Carthage, became more wealthy and powerful than the parent state. The merchandise they gathered from distant countries they distributed through Asia by a land trade, and their caravans reached Nineveh, Babylon and Persia, and, for long periods, were almost the only link that joined Egypt to the rest of the busy and growing world. They learned many useful things among the Egyptians, among others the invention of letters, or at least hints on which they improved. Many flourishing cities were built up by this internal commerce in places surrounded by desert regions, as Baalbek and Palmyra in Syria, and Petra in Arabia, a city excavated in the rocks, which, lying between Syria and Phenicia in the north and the rich districts of Arabia in the south, and between Babylon and Persia on the east and Egypt on the west, became a great mercantile depot. The Phenicians were the busiest and most enterprising people of ancient times. Their vessels reached the shores of England, where they had valuable mines of tin, as of silver in Spain; they visited the northwest coasts of Africa and the Madeira islands, and brought the rich products of India and gold from eastern Africa to the markets of the world. The amount of their contributions to civilization and progress by making known the discoveries and arts of distant nations to each other, by causing roads and inns to be built, and facilitating communication, was immense; as well as by awakening the love of gain and turning the activities of a part of mankind from warlike to more peaceful and useful pursuits. The arts and inventions that have done the most, in the long run, for the improvement of men, as shipbuilding and writing, were communicated from one nation to another. Their commercial routes were the highways over which the intelligent and inquiring Greeks traveled in search of the knowledge which they used for the education of their people. Tyre was destroyed by Alexander B. C. 332; but he replaced it the same year by building Alexandria, at the mouth of the Nile. 26. We have thus seen nations and institutions gradually unfolding, passing through a period of youth, of vigorous organic action, and finally decaying, to give place to another of higher order which inherited all its general gain and proceeded to carry still further the banner of civilization. As this process continues the field widens, and with the increasing number and variety of the elements engaged in acting upon one another, the product becomes more valuable, the organization more complete and the institutions more useful.