Dreikaisereck

Three Emperors' Corner (Polish: Trójkąt Trzech Cesarzy, German: Dreikaisereck, Russian: Угол трёх императоров) is a former tripoint at the confluence of the Black and White Przemsza rivers, near towns: Mysłowice, Sosnowiec and Jaworzno in the present-day Silesian Voivodeship of Poland. During Partitions of Poland, from 1871 to 1918, it marked the border between the countries participating in the partition: Russian Empire, Austria-Hungary, and the German Empire.

It developed in the aftermath of the Partitions of Poland as a result of the border shifts and regime changes in the 19th century, including the annexation of the Free City of Kraków by the Austrian Empire after the unsuccessful Kraków Uprising in 1846. The left bank of the White Przemsza now belonged to the Austrian Grand Duchy of Cracow (part of the Austro-Hungarian monarchy from 1867). While the Upper Silesian right bank of the Black Przemsza had been annexed by Prussia already in 1742, the land between the two tributaries was part of Congress Poland, a de facto protectorate of the Russian Empire according to the Final Act of the 1815 Vienna Congress. However, the spot did not become a Three Emperors' Corner until the Kingdom of Prussia merged into the newly created German Empire in 1871. It remained as such till the dissolution of all three empires in the aftermath of World War I and the establishment of the Second Polish Republic in 1918.