Pickaxe Mountain is a heavily fortified underground site in Iran, near the Natanz nuclear-enrichment complex, which President Trump has threatened to strike. Its importance lies in the possibility that it could protect parts of Iran’s nuclear programme from air attacks, although international inspectors have not been allowed access and its exact purpose remains unconfirmed.

Known in Persian as Kuh-e Kolang Gaz La, the site is about 225km south of Tehran and covers roughly 2.7 square kilometres. Construction began after earlier sabotage and attacks at Natanz; analysts estimate tunnels may lie 80–100 metres underground, potentially beyond the reach of even powerful US bunker-busting bombs. Trump said the US was tracking Iran’s nuclear material and could target the area soon, amid wider US-Iranian hostilities.