Increased Imperialism and Colonial Expansion: The Industrial Revolution led to increased economic power and technological advancement in European nations, which in turn fueled a desire for colonial expansion. European countries competed to acquire colonies and resources, leading to tensions and rivalries among them.
Nationalism and Militarization: The 19th century saw the rise of nationalism, with countries emphasizing their individual cultural and political identities. Patriotism and a desire to protect national interests led to increased militarization and arms buildup, creating an environment conducive to conflict.
Formation of Alliances: As European nations became more powerful, they formed alliances with one another for protection and security. The Triple Entente (France, Britain, and Russia) and the Triple Alliance (Germany, Austria-Hungary, and Italy) were two opposing alliances that created a balance of power and made it difficult for disputes to be resolved peacefully.
The Balkan Powder Keg: The Balkans region of southeastern Europe was an area of conflict and ethnic tension between the declining Ottoman Empire and various Balkan states. The Ottoman defeat in the Balkan Wars further increased tensions and sparked diplomatic crises among the European powers with interests in the region.
Assassination of Archduke Franz Ferdinand: The assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, by a Serbian nationalist was the immediate trigger that set off a chain of events leading to war. Austria-Hungary's ultimatum to Serbia, backed by Germany, initiated a series of diplomatic exchanges, alliances, and military mobilizations that ultimately resulted in the outbreak of World War 1.
In conclusion, while the Industrial Revolution and the Enlightenment provided the background for the rise of nationalism, militarism, and imperial expansion, they did not directly cause World War 1. A complex combination of historical, political, diplomatic, and military factors ultimately led to the start of the war.