Why Is Iran's Fordow Nuclear Facility Hard To Destroy?

Deep beneath the mountains near the city of Qom lies one of Iran’s most heavily guarded nuclear sites: the Fordow Fuel Enrichment Plant. Designed to survive even the most powerful airstrikes, Fordow has become a focal point in Israel’s escalating concerns over Iran’s nuclear ambitions. But why is this site so difficult to target—and why would Israel need US help to even attempt it?