Germany creates a blockade on Great Britain to prevent shipping on the Allies. Any ship approaching was a target for the Germans to destroy
German submarines (aka U-Boats) takes down the Lusitania ship and all passengers which consisted of civillians, including 128 Americans.
Due to America's anger, Germany stops it's submarine warfare.
President Woodrow Wilson publicly advised Germany to cease with restricted U-Boat warfare
Germany puts submarine warfare policies back into place. This angered American's because of the dangers for civilians.
President Woodrow Wilson asks Congress to declare war on Germany
Troops from the United States experience trench warfare in France
President Woodrow Wilson introduces his 14 points idea, a plan to create permanent world peace.
President Woodrow Wilson agrees to send "volunteer" troops to Russia, to assist the White armies in defeating the Reds. This shows a bias that many countries in the Allies shared about the Russian civil war.
The war ends. Germany and the Allies sign an armistice.