The final work "Tunneling hazard" explores the potential risks that engineers with building tunnels in the rock mass can cause serious problems. Uncertainties are related to the nature of the material and the extent of knowledge of the conditions at the site. Construction in the Karst area should be considered separately, as many hazardous situations can occur in such an area. The risk of water breaching and flooding of tunnels is high because the construction of the object or the excavation of materials changes the hydrogeological conditions underground as well as the direction of groundwater flow. The construction of the tunnel itself is extremely complex and demanding, so it is necessary to take into account the health and safety of people during the construction and in the construction of underground buildings. The risks associated with construction costs arise due to the uncertainties mentioned above, so it is necessary to analyse which factors can lead to cost overruns. Sustainable tunnel construction is increasingly being applied, and special attention is paid to recycled materials and energy efficiency.