I know there are lots of ex-military types around here, so I thought I'd post something I was thinking about the other day. What with all the speculation about Israel hitting Iran's nuclear facilities, and the thought that they might be too hard too take out using conventional weapons, how about this? Instead of dropping a single conventional hardened warhead on an underground facility, how about dropping three (or maybe even more), evenly spaced around the facility. You'd need complete air superiority, of course, but would the converging shockwaves be more damaging than direct impacts? Is there a chance that the shockwaves would reinforce each other, maybe causing such pressure that the facility would shake itself to bits?