opswarfare came across a few instances of underground warfare recently, the recent israeli-lebanon war, and the US-vietnam war. opswarfare finds the concept worth further development, as a possible defensive tactic useful for urban warfare scenarios. For a start, having underground tunnels negate (or at least reduce) the damage from air-strikes. They also allow movement of forces under cover, which increases the element of surprise when fighting enemy forces. Definitely worth doing a feature article...watch this space.