The German Empire was a nation-state that existed from 1871 to 1918, unifying various German states under a single imperial government. It emerged after the Franco-Prussian War and was characterized by rapid industrialization and military expansion, becoming a major European power. The empire was ruled by the Kaiser and had a complex political structure, including a parliament known as the Reichstag. Its aggressive foreign policy and militarism contributed to the tensions leading up to World War I, ultimately resulting in its downfall and the establishment of the Weimar Republic in 1919.