A friend of mine writes his name on the wall of the Zweetkamertje (Sweat Room) of Leiden University

It is a tradition that students who obtain a grade write their name on the wall of the Zweetkamertje (Sweat Room). In older days students had to wait in this room before their exams.

The signatures of Winston Churchill and Nelson Mandela are also there, because they both received an honourary doctorate of Leiden University.