Actually a case could be made that WWI was the Russians fault. After the assassination of Arch Duke Ferdinand the Austro Hungarian Empire was threatening the Serbs and it was the Russians that first mobilized for war.
When the Austro Hungarians attacked Serbia the Russians attacked the Austro Hungarians
The Austro Hungarians were aligned with Germany, who was treaty bound to attack Russia
The Russians were aligned with France, who was treaty bound to attack Germany
Germany had punked down France a few decades previously so they already knew the fastest way to get to Paris was thru Belgium, who had a treaty with the United Kingdom