The so-called "long 19th century" was dominated by five major events/trends: (1) Intellectual responses to the Enlightenment, (2) the Industrial Revolution (both the First and Second). (3) the massive social and economic shifts in its wake, (4) the so-called "triumph" of the nation-state (i.e. the rise of nationalism and "states"), and (5) European imperialism. First, introduce each of these aspects of "the Long 19th Century". How did they contribute to the outbreak of World War I? Also, how did they shape the characteristics and course of the war itself? Ultimately, why do you think that World War I is considered the paradigm-shifting conflict that it is?