A second industrial revolution, and 1848's springtime of nations

Between roughly 1870 and 1914, a Second Industrial Revolution built on the first: the Bessemer process made steel cheap and abundant for the first time, electricity began lighting cities and powering factories, oil fueled new engines, and the telegraph let information cross continents in minutes instead of weeks. These advances reshaped daily life -- but they also quietly built the machinery of a far deadlier kind of war than the world had yet seen, a fact that would matter enormously within a few decades. This era also saw science misapplied to politics: Herbert Spencer coined the phrase "survival of the fittest" to apply Charles Darwin's theory of natural selection, developed to explain biology, to human societies and races instead -- a distortion historians call Social Darwinism, later used to justify economic inequality at home and conquest abroad.

In 1848, long before that steel and electricity reshaped the century, a wave of revolutions swept across Europe almost simultaneously, driven by the same liberal and nationalist ideas that had fueled 1789 and the independence movements since. In France, King Louis-Philippe was overthrown and a short-lived Second Republic declared. In the German states, an elected Frankfurt Assembly tried and failed to unify Germany under a liberal constitution. In the Austrian Empire, Hungarian nationalists under Lajos Kossuth rose up, and the powerful chancellor Metternich fled Vienna in disguise. Italian states rose too. Nearly every one of these uprisings was crushed within a year or two by monarchs regaining their nerve -- yet 1848 proved nationalism and liberalism were now permanent, mass political forces that no government could simply ignore, setting the stage for the unification movements you study next.