Critical infrastructures namely the assets, networks, and facilities (e.g. dams, levees, tunnels, retaining walls, and transport foundations) whose failure or degradation may cause catastrophic disruptions to public safety, the economy, or crucial societal services, are increasingly challenged by climate change, extreme weather, geo-hazards, aging, and intensified use. These pressures intersect with the need for structural adaptation to achieve long-term societal goals, including the energy transition. This course explores these challenges by presenting design strategies for climate-resilient and sustainable infrastructures with particular emphasis on complex geotechnical engineering problems and real-world case studies. The course focuses on the interaction between natural hazards and infrastructure systems, including landslide-infrastructure interaction problems, excavation-induced effects, underground constructions, and the resilience of buried and earth-supported structures under extreme conditions. Geotechnical engineering applications are presented in the broader context of global challenges such as climate change, urban sustainability and resilience, resource and energy management, groundwater protection, and the safe operation of critical infrastructure systems. Fundamental principles of soil and rock mechanics are linked to contaminant and heat transport in the subsurface, supporting the design, construction, and maintenance of energy geostructures (e.g., energy piles, walls, and tunnels), geological energy production and storage systems, and environmental geotechnical applications such as contaminated ground containment and site remediation.