This post is also available in: heעברית (Hebrew)

The U.S. military is considering adding a new warfighting domain to U.S. military doctrine: the underground realm. The underground sphere is particularly important in cities, where nearly two-thirds of the world’s population will live by 2040 — and where the Pentagon expects to see more combat. The military doctrine’s domains currently include land, sea, air, space, and cyber — the latter added in 2012. Adding another would reshape spending and strategy, evaluates
Urban environments pose significant challenges for infantry forces. A report published in 2017 by RAND think-tank suggests that the rise of urbanization increases the likelihood that at least some future conflicts will take place in cities. RAND evaluates that when light and mechanized infantry along with armor forces cooperate as effective combined arms teams, they can adapt and apply creativity to produce a decisive effect on urban combat operations.
For this new type of warfare, infantry units will need to know how to effectively navigate, communicate, breach heavy obstacles and attack enemy forces in underground mazes ranging from confined corridors to tunnels as wide as residential streets. Soldiers will need new equipment and training to operate in conditions such as complete darkness, bad air and lack of cover from enemy fire in areas that challenge standard Army communications equipment.
In 2017, the U.S. Army accelerated its push to outfit 26 of its 31 active combat brigades with new tools and training to “fight in large-scale subterranean facilities that exist beneath dense urban areas around the world,” according to In December, the Defense Advanced Research Projects Agency, or DARPA, launched a new Grand Challenge to develop new technologies for underground warfare and intelligence gathering, in order to “rapidly map, navigate, and search underground environments”.