World War I

On June 28, 1914, Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, made a fateful trip to Sarajevo, capital city of Bosnia and Herzegovina, where he and his wife were assassinated. The occupation of Bosnia and Herzegovina by Austria-Hungary led to growing unrest among people in the region who wanted to become part of Serbia once again. The assassination was staged with the help of Serbia, which also wished to reclaim Bosnia and Herzegovina.

Norman Davies notes, in Europe: A History, the quick consequences of the assassination, and the revelation that Serbia was involved. "Within four weeks, the gunshots of Sarajevo brought Europe's diplomatic and military restraints crashing to the ground," Davies writes. On July 28, exactly one month after the assassination, Austria-Hungary declared war on Serbia. An extensive system of preexisting alliances swiftly pulled most other European countries into the war, escalating the conflict. Eventually, Europe, parts...