Shenyang J-8 Finback fighters being towed into one of the China's many “super-hardened” underground air bases Chinese Internet via Aus Air Power Iran's subterranean labs have made news lately, but it's China's bunkers and reinforced underground hangars that have been on the minds of Western military planners for generations.

Sean O'Connor and Dr. Carlo Kopp from Air Power Australia published a monograph on China's underground air bases, and what it would take to bring them down may surprise you.

China began construction of its 40 or so hidden bases in the 1950s and though some have fallen out of military use and are open the public as museums, many are harboring China's newest air fleet.

Coming at the bunkers with bombs aimed at "the front door" likely won't do much to take structures like this out.