Frankfurt is pretty unappealing so we're glad we only spend one night there. The train station, Europe's largest, is unbelievably huge. It's probably the largest enclosed space we had ever been it. Our hotel was fine and very close to the station. We passed many, many strip clubs on our short walk to dinner - lots of bored businessmen in the city. In the morning before our flight we walked to the river and had a good view of the skyline which was interesting to see, as it's very un-Euro feeling. That's about it.