particular strengths in coal, iron (and later steel), chemicals, and railways. The success of German industrialization manifested itself in two ways in the early 20th century; German factories were often larger and more modern than many of their British and French counterparts, but the preindustrial sector was more backward. The success of the German Empire in the natural sciences, especially in physics and chemistry, was such that one-third of all Nobel Prizes went to German inventors and researchers. During its 47 years of existence, the German Empire became an industrial, technological, and scientific power in Europe. Germany also became a great power, building the longest railway network of Europe, the world's strongest army, and a fast-growing industrial base. Starting very small in 1871, in a decade, the navy became second only to Britain's Royal Navy. From 1871 to 1890, Otto von Bismarck's tenure as the first and to this day longest-serving chancellor was marked by relative liberalism at its start, but in time grew more conservative. Broad reforms, the anti-Catholic Kulturkampf and systematic repression of Polish people marked his period in the office. Despite his hatred of liberalism and socialism – he called liberals and socialists "enemies of the Reich" – social programs introduced by Bismarck included old-age pensions, accident insurance, medical care and unemployment insurance, all aspects of the modern European welfare state. Late in Bismarck's chancellorship and in spite of his earlier personal opposition, Germany became involved in colonialism. Claiming much of the leftover territory that was not yet conquered by Europeans in the Scramble for Africa, it managed to build the third-largest colonial empire at the time, after the British and the French ones. As a colonial state, it sometimes clashed with the interests of other European powers, especially the British Empire. After the resignation of Otto von Bismarck in 1890, and Wilhelm II's refusal to recall him to office, the empire embarked on Weltpolitik ("world politics") – a bellicose new course that ultimately contributed to the outbreak of World War I. Bismarck's successors were incapable of maintaining their predecessor's complex, shifting, and overlapping alliances which had kept Germany from being diplomatically isolated. In 1879, the German Empire consolidated the Dual Alliance with Austria-Hungary, followed by the Triple Alliance with Italy in 1882. It also retained strong diplomatic ties to the Ottoman Empire.