The Mainufer — the riverside park on both banks of the Main — is the open-air lung of the city. The north bank, from the Untermainbrücke past the Eiserner Steg to the railway bridge, is a wide promenade lined with plane trees, used by joggers, dog walkers and cyclists at all hours. The south bank, the Schaumainkai of the Museumsufer, is even busier on weekends, with the Saturday flea market (every other week, March to October) drawing thousands.
On summer evenings the Mainufer is the city's preferred picnic spot: families and groups of friends gather on the grass with bottles of beer and Apfelwein, watching the river-cruise boats and the joggers go by. The Museumsuferfest (last weekend in August) is a free three-day festival along both banks, with stages, food stalls and the museums open late — one of the best free events in Germany and the highest-attendance summer festival in Frankfurt.