The European Union is an organisation that has 27 countries as members, so it is not in any city. It has important offices mainly in Brussels in Belgium, but also in Luxembourg and Strasbourg.
The five largest countries in the European Union by area are: 1. France2. Spain3. Sweden4. Germany5. FinlandThe five largest countries in the European Union by population are:1. Germany2. France3....
The European Union is an organisation, not a country, so it does not have a capital city. Some of it's main offices are in Brussels, which is the capital of Belgium.