1. The E. U.'s headquarters are in Brussels. That is the
capital of which country?

Belgium.

Explanation:

Brussels is the capital of Belgium, the seat of the Belgian royal family and the capital of the European Union. This very small town does not attract hordes of tourists like Bruges and Ghent, because it is the main economic and educational center of the country, so you will meet more busy business people than relaxed tourists. However, here you can get a real impression of daily life in Belgium, visit fantastic restaurants, cafes, museums and galleries, many examples of Gothic and Baroque architecture, interesting places like Atomium and, of course, try the famous Belgian chocolates.