What causef the great change that happened in Europe after world war 1?

The First World War shattered empires, gave birth to a slew of new nation-states, fueled independence movements in Europe's colonies, forced the US to become a world power, and paved the way for Soviet communism and Hitler's rise. Diplomatic alliances and commitments made during World War I, particularly in the Middle East, haunted Europeans a century later. The balance-of-power model of international relations was shattered but not destroyed. It took the Second World War to rally enough political forces to usher in a revolutionary fresh method to inter-state connections.

Explanation:

immigrants from northern and western europe continued coming as they had for three centuries, but in decreasing numbers