In Argentina, there are vast and luxuriant valleys, over which the train seems to creep toward the very edge of a horizon which ever recedes as the traveller advances. From time to time, four or five red one-storied houses, clustered behind a station, recall to his mind the fact that this wilderness is actually inhabited. In Brazil, so far as the eye can see, there are ranges of mountains, shadowy even in brilliant daylight, in the midst of which, from time to time, one mountain stands out more distinctly than its fellows. The shadowy hills are those still covered by the primeval forest; the others, those where the timber has been burned off and replaced by coffee plantations; but even here there is no trace of human life. One must travel long hours by railroad before even catching sight of a village. In North America, or at least in its Eastern States, there are vast and desolate tracts. From time to time a village appears, bristling with chimneys. Then the traveller slips on into the deserted country. Another village appears, only in its turn to disappear. Then all at once the train begins to rush through the midst of houses. On, on it goes. The houses never cease to follow it. Huge edifices rise from the midst of the little dwellings like giants from a crowd of dwarfs. Automobiles and trolley cars move through the streets. It is a great city; half a million, a million, two million men are crowded together there in the shadow of a thousand chimneys, surrounded on every side by an almost deserted country. What a strange sight are these wildernesses to a European accustomed to live in one of the crowded countries of the Old World where men have built their houses everywhere, from the shores of the sea up to the highest habitable slopes of the mountains! In observing a phenomenon so novel to his experience, the historian of antiquity is deeply interested; and as he studies it, like so many other Europeans in the presence of the same spectacle, he forgets his own preoccupations. The riddle of America rises before him and the desire of finding an answer to it turns him from his former studies. For America is a true riddle to Europeans. During the past thirty years, not only the United States, but even smaller American countries like Brazil and Argentina, have impressed themselves sharply upon the attention of Europe. The Old World has been compelled to recognise that America has in her turn become a mighty historic force; and that she exercises an influence on the Old World which grows continuously greater. When one reflects that, only a century and a half ago, all these American states were merely poverty-stricken colonies of Europe, harshly exploited by their European masters, one cannot suppress amazement at the rapidity with which their destiny has changed.