What is a major difference between the united nations and the european union?

A major difference between the UN and EU is that the EU tries to create one 'super nation' out of many nations while the UN tries to promote peaceful and ethical relationships throughout the world. Another difference is geography.

A major difference is that the United Nations (UN) aims towards a more peaceful world and ethical relationships between nations, while the European Union (EU) aims towards the creation of a "super nation", constituted of various nations.

Explanation:

Another important difference is that the EU, as the name states, centers mostly one European countries, while all countries can be part of the UN.