This talk will present our contributions in the domain of field-hardened resilient robotic autonomy and specifically on multi-modal sensing-degraded GPS-denied localization and mapping, informative path planning, and robust control to facilitate reliable access, exploration, mapping and search of challenging environments such as subterranean settings. The presented work will, among others, emphasize on fundamental developments taking place in the framework of the DARPA Subterranean Challenge and the research of the CERBERUS (https://www.subt-cerberus.org/) team, alongside work on nuclear site characterization and infrastructure inspection. Relevant field results from both active and abandoned underground mines as well as tunnels in the U.S. and in Switzerland will be presented. In addition, a selected set of prior works on long-term autonomy, including the world-record on unmanned aircraft endurance will be briefly overviewed. The talk will conclude with directions for future research to enable advanced autonomy and resilience, alongside the necessary connection to education and the potential for major broader impacts to the benefit of our economy and society.