Austria-Hungary began to acquire the states of Bosnia and Herzegovina upon the collapse of the Ottoman Empire, and many Serbians were opposed to the new regime
The Black Hand - Serbian super nationalist group that planned to assassinate the Archduke of Austria-Hungary, believing this would lead to an independent Bosnia
The First Battle of Marne involved more than 2 million soldiers along a 125 mile battlefront, with the French pushing back the Germans 40 miles, but resulting in over 250,000 lives lost
The Zimmerman note was a proposal by Arthur Zimmerman to Mexico to declare war on the US, with Mexico to reacquire its old provinces of Texas, New Mexico and Arizona
To transport troops to Europe safely, the US used the convoy system, in which troop transports were surrounded by destroyers or cruisers for protection
In November of 1917, the Bolsheviks took control of the Russian government and withdrew the Russian army from the Eastern Front, allowing the Germans to focus all its forces on the Western Front
US troops did not see action for nearly a year, but were a major factor in WWI, helping defeat the Germans at Chateau-Thierry and Belleau Wood, which prevented the Germans from taking Paris
American women played a vital role in WWI, working as switchboard operators, nurses, typists, bookkeepers, radio operators, electricians, and telegraphers
In 1918, the Germans began to suffer crippling defeats in France, as the war had crippled the German economy and people began to suffer from starvation, leading to armies beginning to surrender