The Junkers were members of the landed nobility inside the state of Prussia (Germanic state). They owned estates that were great and was maintaine and worked by peasants with few rights. These estates are often in Countrysides or in other places inside Germany. Their names have "von" in their names, it indicates they're from the Junkers family. The most famous Junker was Otto von Bismarck, he was the chancellor of the German Empire after he Unified Germany after the Franco-Prussian war or war of 1870, he was removed in power by Kaiser Wilhelm II in 1890.
That's the statue of Otto von Bismarck. He was the most famous of the Junkers of Prussia. And the one who unified Germany