Final answer:
Germany and Italy upset Europe's traditional balance of power.
Step-by-step explanation:
The establishment of Germany and Italy upset Europe's traditional balance of power. After the unification of Germany and Italy in the mid-19th century, these nations emerged as stronger and more dominant forces, challenging the existing power dynamics in Europe.
Germany's rapid rise as an industrial, political, and military force, along with tensions between France and Germany, contributed to the growing instability in the region. The race to build colonial empires, fierce nationalism, and the build-up of military forces further escalated the situation, eventually leading Europe on an inevitable path towards war.