The 3DxVERSE project integrates digital twins, AI and XR/VR technologies to support cities in planning sustainable transport systems, energy-efficient buildings, and improved public services. Focusing on open-source tools and citizen engagement, it empowers urban planners and communities to co-create greener, more livable cities. Pilot cities include Amsterdam, Rotterdam, Almelo, Enschede, Aruba (NL), TimiΘoara (RO), and Hamburg (DE).