Römer SquareConsistently the top recommendation for visitors, and worth allowing a half day rather than squeezing it between other stops.
Local culture beyond the checklistMain Tower and the Museum Embankment are where Frankfurt feels least like a tourist itinerary and most like the actual city.
A well-known second stop: PalmengartenRounds out a first visit nicely alongside the bigger-name sights.
Easy onward travelFrankfurt's transport connections make it simple to extend the trip into the rest of Germany if you have the time.