On the south side of the Hauptstrasse lies Universitätsplatz, with the Old University dating back to 1711.
On its east side, in Augustinergasse, is the Pedellenhaus with the former Student Prison, Karzer, which for many is the most memorable part of a visit to Heidelberg University.
Here, students found guilty of misdeeds (such as dueling or disturbing the peace by singing at night) were incarcerated for 24 hours. While there, they decorated the walls with graffiti that remains today.
The New University was built in 1928-31, behind which rises the Hexenturm, or Witches' Tower, once part of the town's fortifications.
