All interesting places are located around the Old (Upper) Town, where we took a walk.
As in any other historic town, the heart of the Old Town is in the Market Square. The main building here is the 450-year-old Town Hall.
In the Market Square you can see huge flies on one of the houses. This is part of the fairy tale route around the city, which includes more than 10 art objects from the Grimm brothers' fairy tales. 7 flies are from the fairy tale of the Brave Little Tailor.
Here is a map of all objects, you can download it in PDF with description at this link.
From the Market Square we walked upstairs to the castle.
We encountered a few more sculptures along the way.
Marburg Castle towers above the city and is the symbol of the city. It was built in the 13th century as the residence of the Landgraves of Hesse and played an important role in the history of the region. It combines elements of Gothic and Renaissance architecture. In the XVI century it was the site of the Marburg Colloquium, an important theological meeting organized by Martin Luther. Today the castle houses a museum dedicated to the history of Hesse. The hill offers a picturesque view of the city and the surrounding countryside.
We went down the other way, by the steps near the restaurant. Near St. Mary's Church we found a Grimm-style playground.
A PDF map of Marburg can be downloaded here.
Getting there: we parked here 50.807556, 8.765750, it's a convenient place, but there aren't many spaces. The Marburg (Lahn) train station is 1.4 km from the Market Square.