The first workshop around the Untraceable City took place at the Actionable Science for Urban Sustainability Unconference (AScUS 2020) in June 2020. Based on this workshop, we provide an outline for how such a workshop can be organized. We warmly invite lecturers, trainers, student groups, professional societies, and other groups to take any of the topics (or a group of them) and to hold a discussion around this topic using the outlined format below (improvements and changes are most welcome and we invite you to share your experiences with us and others).