Key Events
Sinking of the Lusitania
Zimmermann Telegram and Germany's resumption of Unrestricted submarine warfare
The bloody duels at Arras and Passchendaele
Archduke Franz Ferdinand was assassinated
Trench Warfare
Sinking of the Lusitania
Zimmermann Telegram and Germany's resumption of Unrestricted submarine warfare
The bloody duels at Arras and Passchendaele
Archduke Franz Ferdinand was assassinated
Trench Warfare