The Germans took the lead in industrialization in the 19th century and soon became the greatest European power. Even after two world wars, Germany was still the greatest European power. However, Stalin absolutely destroyed East Germany by destroying private enterprise. When Germany was reunified in the 1990s, there was great tension between West and East Germany because the East Germans were largely indolent because private enterprise had been squashed under Stalin. So I would say that Germany ceased to be the greatest power in Europe when Stalin removed private enterprise.
Germans have made substantial contributions to science, rocketry, and literature (especially Goethe). Germans have also made great contributions to music (Wagner is one of the greatest opera writers). Handel was German, but he lived and worked in the court of King George III in Great Britain. Germany is known for setting the tone for theological currents in Christianity in the 20th century (Bonhoffer, Barth, et cetera).
The Reformation started in Germany; Luther’s defiance of the pope set a powerful precedent for other countries.