its herculean efforts at Trieste and Fiume to create harbors and to connect them by transmontane railroads with the valley of the Danube, the maritime development of this coast is still restricted, and much of Austria’s trade goes out northward by German ports.[442] Farther south along the Dalmatian and Albanian coasts, the deep and sheltered bays between the half-submerged roots of the Dinaric Alps have developed only local importance, because they lack practicable connection with the interior.  This was their history too in early Greek and Roman days, for they found only scant support in the few caravans that crossed by the Roman road to Dyrrachium to exchange the merchandise of the Aegean for the products of the Ionian Isles.  Spain has always suffered from the fact that her bare, arid, and unproductive tableland almost everywhere rises steeply from her fertile and densely populated coasts; and therefore that the two have been unable to cooeperate either for the production of a large maritime commerce or for national political unity.  Here the diverse conditions of the littoral and the wall of the great central terrace of the country have emphasized that tendency to defection that belongs to every periphery, and therefore necessitated a strong centralized government to consolidate the restive maritime provinces with their diverse Galician, Basque, Catalonian, and Andalusian folk into one nation with the Castilians of the plateau.[443]

[Sidenote:  Accessible hinterlands.]

Where mountain systems run out endwise into the sea, the longitudinal valleys with their drainage streams open natural highways from the interior to the coast.  This structure has made the Atlantic side of the Iberian Peninsula far more open than its Mediterranean front, and therefore contributed to its leadership in maritime affairs since 1450.  So from the shores of Thrace to the southern point of the Peloponnesus, all the valleys of Greece open out on the eastern or Asiatic side.  Here every mountain-flanked bay has had its own small hinterland to draw upon, and every such interior has been accessible to the civilization of the Aegean; here was concentrated the maritime and cultural life of Hellas.[444] The northern half of Andean Colombia, by way of the parallel Atrato, Rio Cauco, and Magdalena valleys, has supported the activities of its Caribbean littoral, and through these avenues has received such foreign influences as might penetrate to inland Bogota.  In like manner, the mountain-ridged peninsula of Farther India keeps its interior in touch with its leading ports through its intermontane valleys of the Irawadi, Salwin, Menam, and Mekong rivers.

Low coasts rising by easy gradients to wide plains, like those of northern France, Germany, southern Russia, and the Gulf seaboard of the United States, profit by an accessible and extensive hinterland.  Occasionally, however, this advantage is curtailed by a political boundary reinforced by a high protective tariff, as Holland, Belgium, and East Prussia[445] know to their sorrow.