Final answer:
The European Union is a supranational organization established after World War II to unite European economies and promote peace, It now includes economic integration and a common currency, the euro, but also faces challenges like member compliance and Brexit.
Step-by-step explanation:
The European Union (EU) is an example of a supranational organization, which is a large and influential regional economic institution meant to promote peace, solidarity, and economic integration among European countries. Post World War II, European leaders created the EU, initially starting with a free trade association, evolving into a common market, and finally establishing a full economic union. This was done to tie economies together, reduce the likelihood of conflict, and allow Europe to compete globally.
With a common currency, the euro, the EU has worked towards eradicating trade barriers and facilitating the free movement of goods, labor, and capital across member states. However, the EU has also faced challenges, such as enforcing regulations among its members, like the economic issues with Greece and overfishing disputes with Spain, along with the significant event of the United Kingdom's Brexit.