There are no talks scheduled for Thursday afternoon, so you can either stay at the university, perhaps continue doing some maths, visit Karlsruhe (the castle and sourrounding garden are nearby and very nice), or come with us on a short trip to Durlach (https://en.wikipedia.org/wiki/Durlach).
Durlach is the oldest district of Karlsruhe, founded in the 12th century and part of Karlsruhe only since 1938. We will visit the remains of the Turmberg and spend some time in the historic center of Durlach. Details will be annouced during the conference.
The conference dinner will take place in the restaurant "Badische Weinstuben" (https://badische-weinstuben.de) which is located in the botanical garden of Karlsruhe. We will meet there Thursday evening at 6 o'clock.