Frankfurt is often seen only as a transit hub or a business centre, but it's so much more. It boasts Germany's most spectacular skyline, mirrored in the Main River, and Europe's tallest office building. It's also the country's most international town; more than a quarter of its citizens are foreign.
Frankfurt throws more money at the arts than any other European city so you'll most likely catch a groundbreaking exhibition at one of its museums. And if you do happen to get stuck at the mega-airport there's a nightclub, art gallery and X-rated cinema to help while away those in-transit hours.