This event in Sarajevo ignited World War I.
What is the Assassination of Archduke Franz Ferdinand?
This battle was one of the longest and deadliest, symbolizing trench warfare.
Answer: What is the Battle of Verdun?
This alliance included Germany, Austria-Hungary, and Italy.
Answer: What is the Triple Alliance?
A German U-boat sank this British passenger liner, killing over 1,100 people, including Americans.
Answer: What is the Lusitania?
This treaty officially ended World War I and imposed harsh terms on Germany.
Answer: What is the Treaty of Versailles?
Austria-Hungary demanded Serbia meet these strict conditions after the assassination.
What is Austria-Hungary's Ultimatum to Serbia?
The first use of poison gas by Germany occurred during this battle.
Answer: What is the Second Battle of Ypres?
This agreement between France and Britain resolved colonial disputes and laid the foundation for the Triple Entente.
Answer: What is the Entente Cordiale?
The U.S. officially entered World War I after declaring war on this country.
Answer: What is Germany?
This treaty between Russia and Germany ended Russian participation in the war.
Answer: What is the Treaty of Brest-Litovsk?
The annexation of this region by Austria-Hungary heightened tensions with Serbia.
Answer: What is Bosnia?
This battle halted Germany's advance into France, leading to trench warfare.
Answer: What is the First Battle of the Marne?
Germany proposed an alliance with Mexico in this infamous communication.
Answer: What is the Zimmermann Telegram?
This intercepted communication pushed the U.S. closer to joining the war.
Answer: What is the Zimmermann Telegram?
This empire's unification following the Franco-Prussian War increased European tensions.
Answer: What is the German Empire?
The series of regional conflicts that weakened the Ottoman Empire and fueled tensions in Europe.
Answer: What are the Balkan Wars?
This battle resulted in massive casualties with minimal territorial gain.
Answer: What is the Battle of the Somme?
This crisis saw Germany challenge France's influence in North Africa, increasing tensions.
Answer: What is the First Moroccan Crisis?
American entry into the war was in part due to Germany's policy of unrestricted this.
Answer: What is submarine warfare?
The United States' entry into World War I is considered a turning point for this alliance.
Answer: What are the Allied Powers?
The first nation to declare war, setting off a chain reaction of alliances.
Answer: What is Austria-Hungary?
Germany's invasion of this neutral country prompted Britain to declare war.
Answer: What is Belgium?
This treaty ended Russia's involvement in World War I.
Answer: What is the Treaty of Brest-Litovsk?
This revolution in Russia prompted its withdrawal from World War I.
Answer: What is the Bolshevik Revolution?
This peace treaty redrew European borders and demanded reparations from Germany.
Answer: What is the Treaty of Versailles?