Giessen is well-placed for day trips into central Hesse. Both Marburg and Wetzlar are within 30 minutes by train and offer strong contrasts to Giessen's largely postwar streetscape.
Marburg to the north is the most rewarding day trip from Giessen. The old town survived the war intact and climbs a steep hill above the Lahn, crowned by a large Landgrave castle. It is one of the best-preserved medieval cities in Hesse and easy to reach by regional train.
Wetzlar to the west is another historic town that avoided wartime destruction. It is closely associated with Goethe, who worked there as a young lawyer and drew on his experiences to write The Sorrows of Young Werther. The Dom — an unfinished Gothic cathedral that never received its north tower — is the main landmark.
For those with more time, the Lahn cycle path offers a satisfying way to travel between all three cities on two wheels over a couple of days.