If the Israel Defense Forces conduct a ground campaign in Gaza, the threat of Hamas tunnels will be one of the most significant challenges to contend with. But how many of these tunnels are there? What can Israeli forces do about the tunnels when they encounter them? Can they seal them? Can they destroy them with bunker-buster munitions or other explosives? The answers to these questions are not simple. In this episode, John Spencer welcomes Dr. Daphne Richemond-Barak back to the show. She is a professor at the Lauder School of Government, Diplomacy, and Strategy at Reichman University, author of the book Underground Warfare, and creator of the International Working Group on Subterranean Warfare.