What's the german expressionism and what significant role does the germans play in cinema history?

The German Expressionism consisted of a number of related creative movements in Germany before the First World War that reached a peak in Berlin during the 1920s. These developments in Germany were part of a larger Expressionist movement in the north and central European culture in fields such as architecture, dance, painting, sculpture, as well as cinema.

Sorry i don't know and i am too busy