There is no official capital of the European Union, but, in effect, it is Brussels. There is a massive campus of some of the most dramatic modern buildings in the world.
The campus includes the European Commission, the Council of the European Commission, the European Council and the European Parliament. Some of these buildings house major European summits. President Obama was there for a major summit last year and recently there have been important gatherings on the plight of Greece and immigration in the region.
The buildings, with controversial and overpowering architecture at odds with much of the old city, is one of the few areas where we saw guards with large automatic weapons.
Belgium was apparently chosen as the de-facto headquarters for the EU because it is the most multi-national country in Europe.
None of the buildings, except a couple of information offices, are open to the public.
NATO is also headquartered in Brussels, but we will have to save that for the next trip.