The Israeli Defense Forces say they have found about 1,500 underground tunnels- in Gaza. What they don’t know is how many more are yet to be discovered. Retired Maj. John Spencer, chair of urban warfare studies at the Modern War Institute, says the Hamas tunnel system likely took years, millions of dollars and advanced engineering to construct. More: newsnationnow.com/world/war-in-israel #IsraelHamasWar #HamasTunnels #GazaTunnels #GazaMetro #NewsNation #VargasReports Anchor Elizabeth Vargas delivers the biggest stories, without bias or opinion. Watch "Elizabeth Vargas Reports" every weeknight at 6p/5C on NewsNation. #VargasReports NewsNation is your source for fact-based, unbiased news for all America. More from NewsNation: newsnationnow.com Get our app: trib.al/TBXgYpp Find us on cable: trib.al/YDOpGyG How to watch on TV or streaming: trib.al/Vu0Ikij