The First World War accelerated the path to modernity. It was the "Primal catastrophe" of the 20th century, an era of war, violence and displacement. It cost the lives of around 17 million soldiers and civilians, destroyed large parts of Europe and left behind unresolved problems that led to further violent conflicts.
[Without the First World War, the rise of fascism and communism and the transition to systemic competition between West and East, the 20th century cannot be understood.]
The assassination of the Austro-Hungarian heir Franz Ferdinand and his wife in Sarajevo on June 28, 1914 is regarded as the trigger for the First World War. In Vienna, the military pressed for a swift retaliatory strike against Serbia. The German Reich assured Austria-Hungary of its unrestricted loyalty to the Danube monarchy.
On July 28: Austria-Hungary declares war on Serbia - Russia starts mobilization.
On August 1: The German Empire declares war on the Russian Empire.
August 2: Invasion of German troops in Luxembourg.
August 3: Invasion of German Troops in Belgium - the First World War begins.
The age of weapons of mass destruction and industrial warfare began in early 1915 with the German chlorine gas attack on the Ypernbogen. Almost two million German, French and British soldiers died on the barren battlefields and in the trenches of the "Hell of Verdun" in 1916. However, the course of the front changed only slightly as a result of these material battles.
In total, the war claimed 17 million lives. It ended on November 11, 1918 with an armistice and the defeat of the German Reich. In Germany, the monarchy collapsed and the Weimar Republic was founded.
In 1917/1918, numerous monarchies collapsed in quick succession and were replaced by democratic republics, as was the case in Germany in November 1918.
After 1918, no new stable framework of order was recognizable - neither socially, politically nor internationally.
The new models of the Russian Bolsheviks, the fascists in Italy and the National Socialists in Germany were unmistakably opposed to the liberal legacy of the 19th century, not least in their pronounced willingness to use violence. This had to do with the diverse experiences of world war, the transitions from state war to revolution and civil war, as well as the disappointed expectations in many societies in view of the peace treaties of 1919.