DARPA Hosts Subterranean Challenge to Benefit Warfighters

https://www.defense.gov/News/News-Stories/Article/Article/2790121/darpa-hosts-subterranean-challenge-to-benefit-warfighters/

The goal of the Defense Advanced Research Projects Agency’s Subterranean Challenge was to find breakthrough technologies and capabilities for underground operations.

https://peterholland765.wordpress.com/2021/09/28/darpa-hosts-subterranean-challenge-to-benefit-warfighters/