No war without cause.
Russia entered World War 1 through an alliance with Austria. World War 1 caused much distress with Russia's people. Many weapons came to the hands of peasants. World War 1 was a main contribution to starting the Russian Revolution. The alliance was not with Austria. Russia fought Austria. The alliance was with France against Germany.
Sinking of the U.S. vessel the Lusitania
It was the trigger but not the cause. Please see the related question.
How Did World War 1 Start? The immediate cause for World War 1 was the assassination of the Archduke Franz Ferdinand of Austria and his pregnant wife Sophie. Archduke Franz Ferdinand of Austria was the nephew of Emperor Franz Josef and heir to the throne of Austria and Hungary
the assasination of Franz Fernidad caused an uproar in Germany and austria, causing them to go to war
The most direct cause of World War 1 was that the Archduke Franz Ferdinand of Austria and his wife were assassinated by a Serbian nationalist.
The cause of World War 1 was because of the assassination of Archduke Franz Ferdinand. Ferdinand was the next in line for the throne of Austria. Austria then put the blame on Serbia, starting World War 1.
Austria Hungary did not become one nation after World War 1.
Because Serbia for example wanted to be its own nation from Austria-Hungary.
the assassination of Austrian arch duke Franz Ferdinand by bosnian nationalists caused austria to declare war on bosnia and russia was allied with them and Germany with austria
World War I had many causes, but the primary cause was the assasination of Archduke Franz Ferdinand of Austria while in Sarejevo on June 28, 1914.