Short answers, pulled from the story.
The German Empire, also called the Deutsches Reich or Imperial Germany, was the German state that existed from the unification of Germany in 1871 until the November Revolution of 1918. It lasted 47 years and was a federal monarchy of 25 states centered on Berlin.
The German Empire was founded on the 18th of January 1871, when William I of Prussia was proclaimed German Emperor in the Hall of Mirrors at the Palace of Versailles during the siege of Paris. Its new constitution came into force shortly afterward, and Berlin remained the capital.
Prussia dominated the German Empire because it held about two-thirds of the Empire's population and territory, and the King of Prussia was constitutionally also the German Emperor from the House of Hohenzollern. With 17 of the 58 Bundesrat votes, Berlin needed only a few smaller states to control decisions.
By 1913 the German Empire was the largest economy in continental Europe and the third largest in the world, behind the United States and the British Empire. Its chemical industry produced almost 90% of the world's dyestuffs, and one-third of all Nobel Prizes went to German inventors and researchers.
The Kulturkampf was Otto von Bismarck's campaign against the Catholic Church, waged in Prussia from 1871 to 1880. The May laws of 1873 stripped the Vatican's authority and controlled priestly appointments, and by 1876 every Prussian bishop was imprisoned or in exile, but the policy backfired by strengthening the Catholic Center Party.
The German Empire collapsed in the November Revolution of 1918 after defeat in the First World War, when sailors mutinied at Kiel and Wilhelm II abdicated. On the 9th of November 1918 Philipp Scheidemann proclaimed a republic, the armistice followed on the 11th of November, and the Weimar Republic succeeded the Empire.
The German Empire built the world's third-largest colonial empire, holding territories in Africa, the Pacific and China. In German Southwest Africa it carried out the Herero and Nama genocide in 1906 and 1907, in which some 65,000 Herero and 10,000 Nama perished, an event the United Nations condemned in 1985.