Mainz — Gutenberg's home on the Rhine, with a well-preserved old city, 45 min. by S-Bahn S8
Wiesbaden, wealthy historic spa city and state capital, 45 minutes by S-Bahn S1, S8, S9 or 35 min. by SE10 from Hauptbahnhof
Rüdesheim am Rhein â at the southern end of the Rhine Valley and the Rheingau, 73 min. by SE10.
Darmstadt — former residence of the duchy of Hesse, picturesque old town, art nouveau architecture
Bad Homburg — spa town with close by old Roman fort Saalburg (http://www.saalburgmuseum.de) that is on the UNESCO heritage list
Bad Nauheim — art nouveau buildings and place where Elvis Presley stayed while in the Army 1958-1960
Heidelberg, with famous castle and charming old town, 55 min. by IC.
Cologne, home to the Cologne Carnival and a famous cathedral, 1 hour by ICE
Büdingen: medieval city center
Hiking
If you're keen on hiking, head out to the nearby Taunus mountains, the Vogelsberg an extinct volcano, or the Odenwald.