Abstract. Urban digital twins are becoming increasingly popular across various domains, including urban planning and studies of cultural heritage. However, current digital twins lack an important aspect compared to their physical counterparts: the ability to exchange, discuss, and mediate in a dedicated location around a specific object. We require a place where we can exchange with experts, similar to what we can do on a university campus, and support participative science. In this article, we propose IMUV, a flying campus integrated with the urban digital twin. IMUV not only supports 3D urban visualization but also provides an online space where users can exchange and collaborate in both the real-world and online environments. We describe the conception, development, and evaluation of the proposed platform, highlighting its potential to bridge the gap between physical and virtual urban environments and facilitate collaborative decision-making processes. With the evolution of modes of working, such as remote work, we are also studying how online spaces can go beyond simple video conferencing. This article presents a proof-of-concept that can serve as a basis for such studies.