MAIN causes of WW1
Alliances
Militarism
Imperialism
Nationalism
The assasination of Archduke Franz Ferdinand by a Serb Nationalist named Gavrilo Princip.
The annexation of Bosnia-Herzegovina from Austria-Hungary, which was amongst the two biggest and most important powers in Europe.
This was due to the fact that Russia was Serbia's ally and Russia made it clear that it was going to defend Serbia in case a war began between them.
Countries agreed to aid one another during war.
Glorifying militaries and the reliance of military strength during wars.
Naval race was significant, thus, made countries grow their Naval fleet significantly.
Arms race/competition
When 2 groups of allied countries would go to war, this would lead to huge conflicts.
The desire to expand and the competition for colonies (Scramble for Africa)
Pride
Superiority over other countries
Unification
Wanting independence (own country).
The moroccan Crisis in 1905
Alliances made nations overconfident and reckless. This encouraged national leaders to act recklessly. They knew that if they declared war, other powerful allies were compelled to fight alongside with them.
The Dual Alliance also had a role to play before WW1. It would state that if Austria-Hungary was ever attacked by Russia, Germany would have to intervene and fight off Russia. However, they would remain neutral in case of any aggression by any other power.
The Kaiser of Germany felt that he needed a bigger navy than Britain to protect Germany. While Britain and Germany were building up their navies, many major powers on mainland Europe were also building up their armies.