At 3:51 it is mentioned that Archduke Franz Ferdinand was heir to the Austro-Hungarian empire, but he was the nephew of Franz Joseph. Did Franz Joseph have any legitimate children? And who succeeded him as emperor?
Yes, Franz Joseph had four children but only one of them was a man and he died (suicide) before Franz. As women could not become emperor of Austria Hungary, after Franz Joseph died, Blessed Charles of Austria (Karl Franz Joseph Ludwig Hubert Georg Otto Marie), his grand-nephew, became the emperor
January 18, 1871
Bismarck completes efforts to unify Prussia and the German kingdoms into a single nation and has King Wilhelm I proclaimed Kaiser.
May 10 France forced to sign humiliating treaty with Germany that ends the 1870-71 Franco-Prussian War.
1888 After his father's untimely death, 29 year-old Wilhelm II becomes ruler, Kaiser Wilhelm II, of Germany.
1894 Nicolas is crowned Tsar Nicholas II of Russia, a position he did not want. Germany and Russia do not renew a friendship treaty and begin their adversary relationship.
1901 Great Britain's Queen Victoria, whose bloodline runs through most of the ruling houses of Europe, dies.
1904-1905 Russo-Japanese War results in disastrous defeat for Russia and major civil unrest at home
January 22 "Bloody Sunday Massacre" by Tsarist troops in St. Petersburg left Russian workers dead and cost Nicholas support among the workers and farmers.
1906 British launch first "dreadnought" class battleship.