Final answer:
The long-term causes of World War I encompass Militarism, Alliances, Imperialism, and Nationalism. The assassination of Archduke Franz Ferdinand was the immediate cause that sparked the war, leading to a swift mobilization of nations' armies and the outbreak of conflict which soon transitioned into trench warfare.
Step-by-step explanation:
Main Long Term Causes of WWI
The long-term causes of World War I can be remembered by the acronym MAIN: Militarism, Alliances, Imperialism, and Nationalism. Militarism refers to the arms race and the build-up of armies and navies that created a sense of fear and the need for preparedness amongst countries. Alliances between major powers created a complex network that could quickly escalate a conflict into a full-blown world war. Imperialism, particularly in Africa, heightened tensions as countries competed for colonies and resources. Nationalism led to conflicts as ethnic groups sought self-determination or countries, as a whole, strove to assert themselves.
The "Spark"
The immediate cause, or "spark," that ignited World War I was the assassination of Archduke Franz Ferdinand of Austria-Hungary by a Serbian nationalist in Sarajevo on June 28, 1914. This event set off a chain reaction, invoking alliances and mobilizing armies. Within weeks, the major powers were at war.
The First Few Months of World War I
The first few months of the war included rapid movement and battles, known as the 'war of movement.' As armies mobilized, Germany implemented the Schlieffen Plan intending to quickly defeat France before turning to Russia. However, the Battle of the Marne and the subsequent 'Race to the Sea' led to a deadlock and the start of trench warfare which would characterize much of the Great War.