US President Donald Trump has praised the B-2 stealth bombers used in strikes against Iran, renewing his warning that Tehran will never be allowed to develop nuclear weapons. But what does this mean for Pickaxe Mountain, the heavily fortified underground site near Iran’s Natanz nuclear complex? Trump has previously suggested the US may need to strike the facility, claiming it could be taken out quickly. Its depth and suspected role in Iran’s nuclear programme, however, raise questions about whether conventional bunker-busters can destroy it. Is Washington preparing another strike, or using the threat to pressure Tehran into a deal?