Use this Teacher Curriculum and Crash Course, World History videos to learn about the challenges to European-dominated nations (which also included the United States, Russia, and Japan), over the century. Host John Green addresses WWI, WWII, the Cold War, China’s Revolution, and globalization. This unit addresses the Essential Questions—How did conflict change and impact the 20th century? What patterns have emerged through your study of history? How have those patterns shaped the world we live in today? How might they shape our future?