How to attack Iran's "maze" of nuclear tunnels

Thermobaric bombs like the BLU-118 “cave buster” have been specifically designed for attacking tunnel systems; the shockwave will travel far underground, going around corners and bends that would degrade normal blast waves. One test showed that it could kill human targets even when the blast had traveled through 1100 feet of tunnels.

There are also more exotic options, like the Rocket Balls (or more correctly, “kinetic fireball incendiaries”) developed for the Defense Threat Reduction Agency. A warhead would release a large number of these rubberised balls of rocket fuel; once ignited they bounce around at high speed, spreading out by going through doorways and other openings and raising the surrounding temperature to over a thousand degrees within seconds.

Attacking the Iranian nuclear program would be a massive undertaking, though but not necessarily impossible. However, it would certainly appear that the U.S. is the only nation with the capability to carry out such an attack. As far as we known, Israel lacks both the sensor technology and the munitions for the job.