Jakob Zinsstag is one of a select group of researchers who warned early on about the risks of zoonoses - infectious diseases that can transfer from animals to humans. In this web report, we accompany the epidemiologist and «One Health» pioneer on a journey to the causes of the Covid-19 pandemic. His research shows: If we don’t learn to see humans, animals and the environment as a single unit, the next pandemic is not far away. Jakob Zinsstag has opened his personal archive, spanning 30 years of field research, to us for this web reportage. The illustrations from Seraina Hügli and Lucas Pfister (capisci.ch) are based on his photographs and our personal encounters with the researcher. In collaboration with “NZZ am Sonntag” we created an interactive web-based multimedia report that allows readers to explore the causes of pandemics and possible solutions to avoid them. We delved into important aspects of "One Health" in sub-chapters and interviews with experts.