EITF80 Elektromagnetisk fältteori (E)
The course description is available here.
This course has the reputation of being the hardest one in the Electrical Engineering (E) Program. Let's face it, Maxwell's Equations are not a piece of cake!
Don't take my word for it, hear it for yourself in the following youtube clip (listen to the first minute).
NB. The course is also available as a PhD course (under the course code EITF80F), intended for PhD students that are from a different background than traditional electrical engineering programs.