Isfahan is at the heart of Iran's nuclear program. 

This conversion plant is located outside the city. Powered by three small Chinese-supplied research reactors, it produces fuel for Iran’s civilian nuclear program. These images were shot in March 2005. One of the rare occasions the world got to see inside. 

Deep underground in the wider province of Isfahan is the Natanz uranium enrichment facility. Western nations say Iran is operating a secret weapons program here. Tehran though denies it is developing a nuclear bomb. 

In 2015, after long negotiations, western nations struck a deal with Iran to stop it becoming a nuclear power. Tehran got relief from sanctions, in return for accepting limits on its nuclear activities. 

Federica Mogherini, former EU Foreign Policy Chief (July 14, 2015): "With courage, political will, mutual respect and leadership, we delivered on what the world was hoping for."  

The following year, a new president moved into the White House. In 2018, he made good on one of his election promises. 

Donald Trump, former US President (May 8, 2018): "I am announcing today that the United States will withdraw from the Iran nuclear deal." 

Without US participation, the agreement quickly unravelled. Iranian engineers got back to work. And progress has been swift. The UN nuclear watchdog says Iran is now producing uranium close to weapons-grade levels. 

These nuclear facilities are tempting targets for opponents of the Iranian regime. 

In 2010, a computer virus crippled operations at Natanz. No one has ever accepted resonsibility. But many believed the virus was developed by the US and Israel.

Natanz was again the target in 2021. The power went out here, setting enrichment back by months. Iran called it an act of nuclear sabotage — and blamed Israel.

Back in the present day: Footage claimed to have been shot at the Isfahan facility. Tehran says the site here is safe and undamaged following Israel's strike.