Registration of US men aged between 21 and 31 began for troops for WWI.
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During World War I, Japan officially declared war on Germany.
During World War I, as a soldier, Adolf Hitler was injured by a grenade blast.
During WWI, The Battle of Gallipoli concluded with an Ottoman Empire victory when the last Allied forces were evacuated from the Peninsula.
Franz Ferdinand and his wife Sophie were assassinated, ultimately causing World War I.
The First Battle of the Marne began during World War I.
