The assassination of Archduke Franz Ferdinand in 1914 is widely regarded as the immediate trigger for World War I. This event set off a chain reaction among the major European powers.

The First Battle of the Marne in 1914 was pivotal in halting the rapid German advance and marked the beginning of trench warfare on the Western Front. It is considered the first major clash in that region.

World War I is often called 'The Great War' due to its unprecedented scale and the massive impact it had on the world. This name was used before the occurrence of World War II.

Germany was a leading power of the Central Powers during World War I and fought against the Allies. France, Russia, and the United Kingdom were key members of the Allied coalition in the conflict.

Trench warfare on the Western Front was characterized by static positions and prolonged, attritional battles with little movement. The defense-focused nature of trenches made rapid advances difficult.

The primary alliances during World War I were the Allies and the Central Powers. This division defined the global conflict and shaped the strategies of the involved nations.

Nationalism played a key role in heightening tensions among European nations. Intense national pride and rivalries contributed to the series of conflicts that escalated into a full-scale war.

The overwhelming use of static trench defenses led to prolonged periods of stalemate on the Western Front. This approach minimized rapid movements and resulted in attritional combat.

Chemical weapons, such as chlorine and mustard gas, were introduced during World War I. Their use had a profound and devastating impact on warfare, prompting future international regulations.

The Battle of Verdun, fought in 1916, is notorious for its duration and staggering human cost. The battle epitomizes the brutal, grinding nature of trench warfare.

Italy was initially part of the Triple Alliance with Germany and Austria-Hungary but switched allegiance in 1915 in exchange for territorial promises. This change significantly altered the balance of power in the conflict.

The Zimmermann Telegram was a secret communication from Germany that proposed a military alliance with Mexico against the United States. Its interception helped sway American public opinion toward entering the war.

The Armistice of November 11, 1918, marked the end of active fighting on the Western Front. It was a ceasefire agreement that preceded the formal peace treaties.

The Treaty of Versailles, signed in 1919, was the primary peace treaty that ended World War I. It imposed heavy reparations and territorial losses on Germany.

With so many men fighting on the front lines, women were required to fill roles in factories and other sectors, leading to increased participation in the workforce. This shift was a catalyst for later social reforms and movements for women's rights.

The Schlieffen Plan was crafted to enable Germany to defeat France quickly by invading through neutral Belgium, encircling French forces, and forcing a rapid surrender. This strategy was based on rapid movement rather than prolonged engagements.

The combination of advanced defensive technologies like machine guns and the physical constraints of trench systems made it extremely difficult for either side to achieve a breakthrough. This resulted in a prolonged stalemate on the Western Front.

The disintegration of empires such as Austro-Hungarian, Ottoman, Russian, and German led to the creation of several new nation-states. This redrawing of boundaries significantly altered the political landscape of Europe.

The introduction of machine guns and heavy artillery made offensive operations particularly deadly and favored defensive strategies. This technological shift contributed significantly to the high casualty rates of the war.

Economic hardship, societal upheaval, and harsh post-war treaties paved the way for the rise of totalitarian regimes in several European countries. This shift in political power had lasting implications for global politics throughout the century.