Hamburg. The commemoration is hosted by a different city each year.
What is the German concept of unity and nationalism? At least I see its manifestation everyday. Outside town halls, in cars, gardens, in my office, and of course, in international football games, the tri-band German flag is a common sight. In the Philippines, you can't see this national pride in practice, probably because it is considered baduy (out of style, uncool) to show one's nationalism. Although we sing our national anthem in school every morning and in public offices and universities on Mondays. Come to think of it, we're not any less nationalistic: Germans just do it visually, while we do it orally!