World War I, which is often referred to as the Great War, had multiple beginnings and consequent effects.

The major causes are:-

1. Militarism: As a result of an arms race among European countries, tensions rose with the growth of armies and navies.
2. Alliances: Europe was divided into hostile camps by such complex coalitions as the Triple Entente (France, Russia and Britain) and the Triple Alliance (Germany, Austria-Hungary and Italy).
3. Imperialism: Rivalries among the major powers were intensified by their scramble for colonies and global supremacy.
4. Nationalism: Governments embraced aggressive policies in order to assert their authority while ethnic groups sought independence through wars.
5. Assassination of Archduke Franz Ferdinand: Consequently Serbia was invaded by Austria-Hungary after heir to the throne had been assassinated by a Serbian nationalist.

The major consequences are:-

The cost of human life is higher than 160,000 deaths and 220,000 injuries.
1. Political changes: The World War I led to the collapse of empires (Russian, Ottoman, Austro-Hungarian, and German) and the creation of new states such as Russia, Turkey, Hungary, Austria, and Germany.
2. Economic impact: This put the European country under massive financial pressure, leading to a recession.
3. Social Impact: A change in society has led to a greater role for women in the workplace.
4. Treaty of Versailles: Germany was severely compensated for economic difficulties and political instability, paving the way for the rise of Adolf Hitler to power and contributing to World War II.