The German Empire was a nation-state that existed from 1871 to 1918. It was formed after the unification of various German states, led by the Kingdom of Prussia. The empire was characterized by a strong industrial economy and a powerful military, becoming one of the leading nations in Europe during its time. The German Empire was ruled by the Kaiser, who held significant authority. Its political structure included a federal system with various states, each having its own government. The empire ended after its defeat in World War I, leading to the establishment of the Weimar Republic.