Themes Microtunnels Conventional Tunnels Mechanized Tunnels Mining Tunnels Submerged Tunnels Tunnels in challenging conditions: historical cases and lessons learned Concrete materials (designed, molded), treatments, etc. Instrumentation / monitoring (tunnels under construction and operation) Robotics and automation innovations BIM, Big Data and Digital Twin Safety risk, operation of underground structures Contractual practices, insurance, and project management Operation and Maintenance of Railway Tunnels Geological-Geotechnical Investigations and Models Sustainability of solutions in Tunnels and Underground Works Innovation and Sustainability in Underground Mining