Secret diplomacy was a major factor based on the fact that led to fear between all the nations and confusion. Nationalism and imperialism is a factor, scramble for Africa, Archduke fradana has some ties based that his death lead to more retaliation in the Balkans which wanted to be independents do Austria-Hungary and Russia fought over for.
A the reason is because giants in norse represent chaos to the people
He used diplomatic maneuvering alliances to increase French territory and centralize its government.
The Europeans treated the Africans really cruel. The Europeans were trading with the Africns but then they decided to trade the Africans as slaves.
hope this helped ;D