What are 3 reasons World War 1 started?

The three reasons World War I started was:

• Imperial rivalries between different empires: British, French, Russian vs German, Austrian, Ottoman Empires.

• Nationalistic pride between different countries of the time

• Secret alliances that aimed to secure one’s own interest.

The true spark came when the assasiantion of the heir to the Austrian throne occurred. It would set off a chain of events that would bring Europe and by extension, most of the world in direct conflict.

For further reading check the following articles:

• World War I
• World War II
• Causes of World War I