The complex web of alliances, rivalries, and tensions that led to the outbreak of World War I can be analyzed through the following factors:

Alliances:

1. Triple Entente: France, Russia, and Britain formed an alliance to counter the growing power of Germany and Austria-Hungary.
2. Triple Alliance: Germany, Austria-Hungary, and Italy formed an alliance to counter the Triple Entente.
3. Balkan Alliances: Serbia, Bulgaria, and Greece formed alliances to counter the influence of Austria-Hungary in the Balkans.

Rivalries:

1. German-British rivalry: Germany and Britain had a long-standing rivalry over naval power, trade, and colonial territories.
2. Austro-Serbian rivalry: Austria-Hungary and Serbia had a deep-seated rivalry over Balkan territories and national identity.
3. Russian-German rivalry: Russia and Germany had a rivalry over influence in the Balkans and the Middle East.

Tensions:

1. Imperialism: The scramble for colonial territories and resources created tension among European powers.
2. Nationalism: The rise of nationalism in Eastern Europe and the Balkans created tensions between nations and empires.
3. Militarism: The buildup of military forces and the glorification of war created a sense of inevitability among European leaders.

Key events:

1. Assassination of Archduke Franz Ferdinand: The assassination of Archduke Franz Ferdinand by a Serbian nationalist in June 1914 sparked a chain reaction of events that led to the outbreak of war.
2. Austria-Hungary’s ultimatum: Austria-Hungary issued an ultimatum to Serbia, which Serbia refused to comply with, leading to Austria-Hungary’s declaration of war on Serbia.
3. Russian mobilization: Russia mobilized its military in response to Austria-Hungary’s declaration of war on Serbia, which led Germany to declare war on Russia.
4. German invasion of Belgium: Germany invaded neutral Belgium, which led Britain to declare war on Germany.