Which war concluded with the unification of Germany following Bismarck's policies?

The Franco-Prussian War, fought between 1870 and 1871, was pivotal in the unification of Germany, largely due to the strategic and diplomatic efforts of Otto von Bismarck. Bismarck utilized nationalism and the growing tensions between France and the German states to rally the German principalities against a common enemy. The war concluded with a decisive victory for the German states, particularly Prussia, over France.

The successful outcome of the Franco-Prussian War resulted in the proclamation of the German Empire in January 1871 at the Palace of Versailles, marking the formal unification of Germany under Prussian leadership. This event signified not only military achievement but also the culmination of Bismarck's efforts to unite the various German states through a series of wars, ultimately solidifying Prussian dominance in German affairs.

In contrast, the other wars listed did not directly lead to the unification of Germany in the same way. World War I and World War II involved a broader set of geopolitical factors without resulting in German unification, while the Napoleonic Wars were earlier conflicts that influenced German nationalism but did not achieve the unification that Bismarck realized through the Franco-Prussian War.