EUROPEAN EMPIRE: Britain, France, Germany, Russia, Austria-Hungary
NEW IDENTITIES (NATIONALISM)
Different cultures, languages, and ethnicities within an empire weakening the empires.
NEW POWERS: Japan, USA, Europe not the only source of power; many countries are much bigger.
NATIONALISM: Identification with one's own nation and support for its interests, especially to the exclusion or detriment of the interests of other nations.
IMPERIALISM: A policy of extending a country's power and influence through diplomacy or military force.
MILITARISM: Beliefs or desires of a government or people that a country should maintain a strong military capability and be prepared to use it aggressively.
ARMS RACE: A competition between nations for superiority in the development and accumulation of weapons.