Reword this and make it shorter:
The pursuit of colonies and resources by imperialist powers led to intense competition and the formation of rivalries among European nations. Nationalism fostered a sense of superiority and competitiveness among countries, resulting in conflicts over territorial claims and spheres of influence. The arms race, fueled by militarism, saw nations investing heavily in their military capabilities to surpass their rivals. Furthermore, the intricate web of alliances created a complex network of obligations that could draw multiple countries into conflicts. These factors collectively contributed to a highly volatile and tense environment that ultimately culminated in the outbreak of World War I.