ITACUS believes in an urban underground future. The urban underground space in our experience is an often-overlooked asset of cities. As such underground space should play a vital role in the quest, many cities are undertaking to combat lack of space. Cities need space for housing, for infrastructure and public spaces. As demands on cities grow in terms of spatial requirements, they also must cope with climate change. They need to become more resilient against natural disasters. Cities need to mitigate and above all, adapt. The urban underground can provide solutions for helping cities achieve this. ITACUS has launched activity groups dealing with relevant topics, such as urban adaptability, urban sustainability, urban integration, and the circular economy, and is thus contributing to the further development of this important field.