Today and tomorrow I am visiting the beautiful city of Zurich. I was invited by Jaiyul Yoo to give a seminar (“Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension”, slides here) at the Department of Astrophysics of the University of Zurich, and I will also be paying a quick visit to ETH, mostly to catch up with my former student Alex Reeves. It has been a very interesting and productive visit so far, and I learned a lot about what one could call using the umbrella term of “relativistic effects” in galaxy surveys, the study of which is something where Jaiyul’s group is probably one of the leading groups in the world. Non-scientific highlights included a fantastic Spanish dinner, and a very enjoyable drive through the Alps!