What shift in global power characterizes the beginning of the modern era?

What best explains why democratic governments failed in many European nations after World War 1? How did The Glorious Revolution contribute to democracy? Which was the most signifacant result of Vespucci's voyage? What were the early forms of currency? Which country was the richest and powerful in the 16th century? When did cordoba fall and to whom? What was the number of deaths during ww1? What led to a reunited Germany? What was the value of the shilling compared to the British pound in 1842? What country was Coco Chanel from? Who became president of Germany after World War 1? What type of money did they use in the 14th century? What are the reasons of decline of the Arab Empire in the Middle East? What was the surname of the last Russian royal family? Why did European countries join the world war 1? Where did Wilhelm roentgen go to school? How was the sepoy rebellion a clash of cultures? Who was Jack the Rammer? What did Albert Einstein have to do with WW2? How did world war 2 help unemployment?