The financial city goes hand in hand with old town, Römer are one point of interest, and some parks near Berger strasse.
Frankfurt is a financial center in Germany. A lot of the older architecture was destroyed in WWII, but there is a smaller altstadt or old city. There are some really creative buildings. The city has several museums, and most are clustered on the south bank of the Mainz river that runs through the city. Lots of good restaurants as well.
This city really depends on when you visit as there isn't a huge amount to do and it can be labelled as a bit soulless compared to some other more exciting German cities. However, come in December when the Christmas markets are in full swing and you will find that there is plenty to keep you occupied. The markets are excellent and photogenic, the Zoo is excellent and there are some great restaurants.
Old tower and nice area near train station and also open air. Look cool when it sunny and sitting out with chill beer