The targets in Iran would vary.
The first would be Natanz, Iran’s main uranium enrichment facility. The complex consists of two large halls, roughly 300,000 square feet each dug somewhere between eight and 23 feet below ground and covered by several layers of concrete and metal. The walls of each hall are estimated to be approximately two feet thick. The facility is also surrounded by surface-to-air missiles.
The next facility would be the heavy-water plant under construction near the town of Arak, which could be used one day to produce plutonium. Iranians say the material will be used for medical and research isotope production, but in reality could have the ability to produce plutonium for nuclear weapons.
Next is Iran’s Uranium Conversion Facility (UCF), located at the Isfahan Nuclear Technology Center. Based on satellite imagery, the facility is above ground, although some reports have suggested tunneling near the complex.
And then there is Fordow, the uranium enrichment facility near the city of Qom, not far from the Caspian Sea. Officially revealed to the IAEA in 2009, the facility can hold thousands of centrifuges. Built into a mountain, it would be difficult to penetrate the hardened facility. Former defense minister Ehud Barak has noted more than once that the facility is “immune to standard bombs.”