“Poor but sexy” is how mayor Klaus Wowereit described Berlin five years ago. Today he might add “grown-up”; the once achingly hip Mitte is now borderline bourgeois, full of modern hotels and gastronome temples, while the city’s artistic hub has migrated to a formerly rough-around-the-edges stretch of Potsdamer Strasse. Kreuzberg—with its pint-size cafés, one-off boutiques, … More What to See and Do in Berlin