By 1846, 180 steamers plied German rivers and Lake Constance, and a network of canals extended from the Danube, the Weser, and the Elbe rivers. As important as these improvements were, they could not compete with the impact of the railway. German economist Friedrich List called the railways and the Customs Union "Siamese Twins", emphasizing their important relationship to one another. He was not alone: the poet August Heinrich Hoffmann von Fallersleben wrote a poem in which he extolled the virtues of the Zollverein, which he began with a list of commodities that had contributed more to German unity than politics or diplomacy. Historians of the German Empire later regarded the railways as the first indicator of a unified state; the patriotic novelist, Wilhelm Raabe, wrote: "The German empire was founded with the construction of the first railway..." Not everyone greeted the iron monster with enthusiasm. The Prussian king Frederick William III saw no advantage in traveling from Berlin to Potsdam a few hours faster, and Metternich refused to ride in one at all. Others wondered if the railways were an "evil" that threatened the landscape: Nikolaus Lenau's 1838 poem An den Frühling (To Spring) bemoaned the way trains destroyed the pristine quietude of German forests. The Bavarian Ludwig Railway, which was the first passenger or freight rail line in the German lands, connected Nuremberg and Fürth in 1835. Although it was long and only operated in daylight, it proved both profitable and popular. Within three years, of track had been laid, by 1840, , and by 1860, . Lacking a geographically central organizing feature (such as a national capital), the rails were laid in webs, linking towns and markets within regions, regions within larger regions, and so on. As the rail network expanded, it became cheaper to transport goods: in 1840, 18 Pfennigs per ton per kilometer and in 1870, five Pfennigs. The effects of the railway were immediate. For example, raw materials could travel up and down the Ruhr Valley without having to unload and reload. Railway lines encouraged economic activity by creating demand for commodities and by facilitating commerce. In 1850, inland shipping carried three times more freight than railroads; by 1870, the situation was reversed, and railroads carried four times more. Rail travel changed how cities looked and how people traveled. Its impact reached throughout the social order, affecting the highest born to the lowest. Although