First World War
The murder on June 28th 1914 of Archduke Franz Ferdinand of Austria was the immediate trigger to cause the first world war. After the Ottoman Empire got involved in 1914, new war fronts started in 1915 causing Italy and Bulgaria to get involved in this complex conflict also.
The Triple Entente with the countries of France, United Kingdom, the Russian Empire (up to 1917), Italy (from 1915) and the United States (from 1917) joined forces to battle against de Central Powers formed by the Austria-Hungarian Empire, Germany, Bulgaria and the Ottoman Empire.
1. Military alliances in 1914, Italy is still part of the Central Powers.
At the end of the war, four of the participating countries where defeated politically as well military. Germany and the Russian Empire where defeated and the Austria-Hungarian Empire and the Ottoman Empire even ceased to exist any longer. The Russian Empire was formed into the revolutionary Soviet Union while in Europe many new countries where formed.
2. The "new formed" Europe after WW1.
The League of Nations was established to prevent escalation and the cause of a new world war in the future. But as a result of the first World War nationalism came up in Europe. The loss of Germany in combination with the consequences of the Treaty of Versailles led directly to the start of the Second World War in 1939.
World war in the Adriatic
During World War I the Austrian Hungarian Navy had their main ports in Pula, and off course they put everything into work to make defence of this port as easy as possible for themselves. Since Italy was not one of their collaborative countries anymore, the Austrian Hungarian army had a big coastal line to defend. Crossing the Adriatic from Italy and vice versa was just easy. Also the German army tried to close the Adriatic sea in the complete South by use of submarines to avoid ships leaving and entering the Adriatic.
During the Adriatic Campaign of World War I, soldiers of the Austro-Hungarian Empire set up extensive minefields along the waters of the Istrian Peninsula, in Croatia. With just a few small mine-free canals to approach Pula, these open canals where quit easy to defend with the use of strategic viewpoints like Brijuni Island and Ližnjan.
3. Austro-Hungarian soldiers with an sea mine. The same type which most likely caused the Cesare Rossarol to sink
4. Overview of the extensive mine fields around the Pula area