It was so LONG. It started with a 45-minute interview with the head of the department, where he asked about my experience and did a brainteaser. A week later I spoke to the VP of the department for one hour, where he asked very similar questions. Then I was invited to a recruitment day which lasted 3 hours. There was a presentation and then 2 back to back interviews. Again, they asked very similar questions about my experience, and how I work. After that, I was rejected and never got any feedback on why. I thought this was really bad after I invested a lot of time and effort.