The important military conflict fought in Europe from 1914 to 1918 was World War I. It involved many of the world's great powers and was marked by trench warfare and significant technological advancements in weaponry. The war began mainly due to political tensions, alliances, and nationalism, culminating in the assassination of Archduke Franz Ferdinand of Austria. The conflict resulted in unprecedented casualties and destruction, reshaping national borders and leading to major political changes, including the rise of totalitarian regimes.