American Imperialism
American business interests helped overthrow the monarchy of this Pacific island chain in 1893, but President Cleveland initially refused to annex it.
Hawaii
The explosion of this American battleship in Havana Harbor helped push the United States toward war with Spain.
USS Maine
Gavrilo Princip was connected to this Serbian nationalist organization that sought to weaken Austro-Hungarian control in the Balkans.
Black Hand
This condition could develop after soldiers' feet remained wet and cold for long periods even though the temperature was above freezing.
Trench foot
Germany's 1915 sinking of this British passenger liner killed nearly 1,200 people, including 128 Americans, and increased anti-German sentiment in the United States.
Lusitania
Proposed while the war was still being fought, this Wilson program called for ideas such as self-determination and a League of Nations.
Fourteen Points
During WWI, these animals carried messages, located wounded soldiers, and could even help warn troops of poison gas—sometimes wearing their own gas masks for protection.
Dogs
After European nations established spheres of influence in China, John Hay proposed this policy to protect American access to Chinese markets.
Open Door Policy
Before going to war with Spain, Congress passed this amendment promising that the United States would not annex Cuba.
Teller Amendment
Germany's advance toward Paris was stopped at this September 1914 battle, helping turn the Western Front into a stalemate.
Battle of the Marne
This deadly stretch of exposed ground separated opposing trench systems on the Western Front.
No Man's Land
This intercepted German message proposed an alliance with Mexico, promising help in recovering Texas, New Mexico, and Arizona if Mexico went to war against the United States.
Zimmermann Telegram
The Constitution gave this part of the U.S. government the power that ultimately prevented American ratification of the Treaty of Versailles.
Senate
In 1906, this president became the first sitting U.S. president to travel outside the United States when he visited Panama.
Theodore Roosevelt
Before the United States took over construction, engineers from this country had already attempted—and failed—to build a canal across Panama.
France
Theodore Roosevelt became nationally famous after leading this volunteer cavalry unit during the Spanish-American War.
Rough Riders
Germany's war planning assumed this eastern power would take longer to mobilize, giving Germany time to defeat France first.
Russia
Germany's Zeppelin airships relied on this highly flammable lifting gas, which contributed to their vulnerability once enemy defenses improved.
Hydrogen
Passed just weeks after the U.S. declaration of war, this 1917 law provided the manpower needed to expand a relatively small peacetime American army.
Selective Service Act
Created by the postwar settlement championed by an American president, this organization began operating without the United States among its members.
League of Nations
This unpredictable force of nature could make poison gas dangerous even to the army that released it by blowing the gas back toward its own lines.
Wind
This 1900 uprising attempted to drive foreign influence out of China.
Boxer Rebellion
This treaty ended the Spanish-American War and transferred Puerto Rico, Guam, and the Philippines from Spanish to American control.
Treaty of Paris (1898)
This country belonged to the Triple Alliance before WWI but remained neutral when the war began and later entered the war against its former allies.
Italy
The defensive combination of barbed wire and this weapon helped make the traditional infantry charge disastrously ineffective on the Western Front.
Machine gun
Created after America's entry into WWI, this force placed U.S. troops in Europe under the overall command of General John J. Pershing.
American Expeditionary Forces (AEF)
Signed in 1919, Germany was excluded from negotiating this peace settlement and was later required to accept its terms.
Treaty of Versailles
During the Battle of the Marne, hundreds of these ordinary Paris vehicles were pressed into service to rush French troops toward the front.
Taxis
This 1890 law hurt Hawaii’s sugar economy by eliminating the trade advantage Hawaiian sugar had enjoyed in the United States.
McKinley Tariff
American forces fought Spain in this Pacific territory, which Spain later surrendered to the United States under the Treaty of Paris.
Philippines
Built on the assumptions that Russia would mobilize slowly and France could be defeated quickly, this German war plan required an invasion through neutral Belgium.
Schlieffen Plan
Nicknamed after a member of the Krupp family, this enormous German artillery weapon was used against heavily fortified positions early in the war.
Big Bertha
This American regiment spent 191 days in frontline trenches and, despite serving under French command, became one of the most celebrated American units of WWI.
Harlem Hellfighters / 369th Infantry Regiment
The reparations bill imposed on Germany was eventually set at roughly this amount in 1921, measured in U.S. dollars at the time.
$33 billion
Before a German U-boat sank the Lusitania in 1915, the ship had departed New York City and was headed for this port city in England.
Liverpool