The valley of the Po would never have attained its importance in the history of Europe unless roads had been constructed for traversing the obstructive mountains which surround it on all sides except towards the east, where it opens out upon the Adriatic. No other district of Europe is so completely hemmed in by natural obstacles as is this, but the construction of carriage roads and railways has converted Northern Italy into one of the great centres of European commerce. Venice gives it the command of the Adriatic, the Apennine railways connect it with Genoa, Savona, the Gulf of Spezia, and the Tyrrhenian, and it thus commands the two seas which wash the shores of Italy. Other railways cross the Alps, and put it into communication with France and Germany. This central position, joined to the natural fertility of the country, has converted Northern Italy into one of the most flourishing portions of Europe. Human hands have conquered original geographical disadvantages, and the true centre of Italy is in the ancient Cisalpine Gaul, and not at Rome. Had the Italians been guided in the choice of their capital by actual importance, and not by historical tradition, they would have chosen one of the great cities of their northern plain. [Illustration: Fig. 75.—THE PASSAGES OVER THE ALPS. Scale 1 : 6,000,000.] Turin, though an old town, seeing that it was burnt by Hannibal, is nevertheless a modern city, if we compare it with other towns of Italy. Its straight and broad streets almost give it the appearance of a town of the New World. Until made a ducal residence, Turin was but a small provincial town. During the time of the Romans, and even during the Middle Ages, the great high-road between Italy and Gaul led along the coast of the Gulf of Genoa. The passage of the Alps was looked upon with dread by travellers. Still some traffic went on even in these {225} early days, and small towns sprang into existence at the foot of each Alpine pass. Amongst these were Mondovi, the triple town built on three hills; Cuneo, favourably placed upon a terrace between Stura and Gesso, in which rise the hot sulphur springs of Valdiera; Saluzzo, on the gentle slope of the foot-hills of Monte Viso; Pinerolo, with its ancient castle, so often converted into a prison of state; Susa, the Italian key of Mont Cenis; Aosta, still abounding in Roman antiquities; Ivrea, built on a site formerly occupied by a glacier descending from Monte Rosa; and Riella, with its flourishing woollen industry. The towns lower down in the plain, upon which several of these Alpine roads converged, likewise attained some local importance. In Upper Piemont there are Fossano, on a heap of shingle at the junction of the roads of Mondovi and Cuneo; Savigliano, lower down, where the roads of the Po and Maira valleys join; and Carmagnola, which commands one of the principal roads over the Apennines. Novara, the commercial outlet of the Lago Maggiore, and in the midst of one of the most productive