by @Chris
From the Congress of Vienna to Sarajevo: a century of nationalism redraws Europe. Italy and Germany unite out of a patchwork of kingdoms and duchies, the multi-ethnic Ottoman Empire is pushed out of the Balkans by new nation states (Greece, Serbia, Romania, Montenegro, Bulgaria, Albania), and the Austrian Empire becomes the dual monarchy of Austria-Hungary. Fifty moments show the treaties, wars, revolutions and uprisings in between. Two red overlays mark foreign army occupations and uprisings or revolutionary zones; border bands show the Zollverein (1834–66) and the North German Confederation (1867–70). Borders: OpenHistoricalMap (CC0) where available, otherwise modern provinces (Natural Earth) and Cliopatria (CC BY 4.0); front lines, occupation and uprising zones are approximate. Sources: the treaties from Vienna (1815) to Bucharest (1913), among them Adrianople (1829), London (1832, 1839, 1864, 1913), Zurich and Turin (1859–60), Vienna, Gastein and Prague (1864–66), Frankfurt (1871), San Stefano and Berlin (1878), Constantinople (1881, 1897, 1913); event details from Wikipedia and standard histories.
Russian Empire · Kingdom of Poland (Russian) · Grand Duchy of Finland (Russian) · Ottoman Empire · Other German states (German Confederation) · Prussia → German Empire · Kingdom of Bavaria · Kingdom of Württemberg · Grand Duchy of Baden · Kingdom of Saxony · Kingdom of Hanover · Electorate of Hesse (Hesse-Kassel) · Grand Duchy of Hesse (Hesse-Darmstadt) · Duchy of Nassau · Mecklenburg · Grand Duchy of Oldenburg · Duchy of Brunswick · Thuringian states · Free cities (Hamburg, Bremen, Lübeck, Frankfurt) · United Kingdom · France · Spain · Portugal · Switzerland · Netherlands · Belgium · Luxembourg (Dutch king until 1890) · Denmark · Sweden · Norway (union with Sweden until 1905) · Austrian Empire → Austria-Hungary · Hungary (revolutionary state 1848–49; kingdom in Austria-Hungary from 1867) · Bosnia-Herzegovina (Austro-Hungarian occupation) · Free City of Kraków · Kingdom of Lombardy–Venetia (Austrian) · Sardinia-Piedmont → Kingdom of Italy · Papal States · Kingdom of the Two Sicilies · Tuscany, Parma and Modena · Duchy of Lucca · Serbia · Montenegro · Wallachia → United Principalities → Romania · Principality of Moldavia · Bulgaria · Eastern Rumelia (autonomous) · Greek insurgents → Kingdom of Greece · Ionian Islands (British protectorate) · Cretan State (autonomous) · Albania · Foreign army occupation · Uprisings and revolutionary zones · Zollverein (German customs union) border · North German Confederation (1867–71) border