Tanks were used for the first time in battle, at the Battle of the Somme, during World War I.
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The US declared war against Germany and its Central Powers Alliance in World War I.
Unofficial ceasefires sprang up across World War I's Western Front.
During WWI, The Battle of Gallipoli concluded with an Ottoman Empire victory when the last Allied forces were evacuated from the Peninsula.
The Red Baron is killed.
Medical researcher Oswald Hope Robertson performed the first-ever blood transfusion using stored and refrigerated blood.
