On 18 January 1871 as the Siege of Paris raged a couple of miles away King Wilhelm I of Prussia was proclaimed Emperor of the German empire in the Hall of Mirrors at the Palace of Versailles. It was the most dramatic possible beginning to a new imperial project in the heart of Europe. The German Empire was instantly a major power on the continent and quickly developed global ambitions. Dan talked to Katja Hoyer about the events leading up to its founding and what it meant for German and the world.