Derek,
Like you said, underground facility is great way of concealing military weapons and troop movements. U.S. suffered greatly during the Vietnam the war although we had much advanced weaponries due to their underground guerilla fighting tactics. Although modern technology has made it possible to detect underground activities but it is very difficult to detect underground activities. North Korea is one the most notorious for its underground nuclear weapons programs. Demick insists that virtually everything of military significance is manufactured underground, whether it be buttons for soldiers' uniforms or enriched uranium for nuclear weapons. South Korean intelligence source estimates that there are several hundred large underground factories
Like you said, underground facility is great way of concealing military weapons and troop movements. U.S. suffered greatly during the Vietnam the war although we had much advanced weaponries due to their underground guerilla fighting tactics. Although modern technology has made it possible to detect underground activities but it is very difficult to detect underground activities. North Korea is one the most notorious for its underground nuclear weapons programs. Demick insists that virtually everything of military significance is manufactured underground, whether it be buttons for soldiers' uniforms or enriched uranium for nuclear weapons. South Korean intelligence source estimates that there are several hundred large underground factories