The attack on Iran's three main nuclear sites was the largest operational strike ever by B-2 stealth bombers, and the second-longest B-2 operation ever flown, surpassed only by those following the September 11, 2001, attacks on the United States by al Qaeda.

Iran has more than thirty nuclear facilities spread out across the country, with several built deep underground. Here's a look at those that have been or could be targeted in the U.S. and Israeli operations, the damage some have sustained so far, and the possible consequences of striking nuclear facilities.

Natanz. The nuclear complex, about 250 kilometers (150 miles) south of the capital Tehran, is considered Iran's largest uranium enrichment facility. Analysts say it is used to develop and assemble centrifuges for uranium enrichment, a key technology that turns uranium into nuclear fuel.