Why did nationalistic rivalries develop between European countries during the early 1900's?

Nationalistic rivalries in Europe during the early 1900s developed due to several factors, including competition for colonial expansion, economic dominance, and military power. Countries sought to assert their national identity and superiority, often leading to tensions over territory and resources, particularly in Africa and Asia. Additionally, the rise of nationalist movements within multi-ethnic empires, such as Austria-Hungary and the Ottoman Empire, further fueled conflicts and heightened competition among European nations. These rivalries ultimately contributed to the outbreak of World War I.