Protests in Iran have intensified this week, sparked by the death of a Kurdish woman in police custody - and buoyed by wider anger at the treatment of women in the republic.
22-year-old Mahsa Amini had been detained by morality police in Tehran for not wearing her hijab correctly. Authorities claim she suffered "sudden heart failure", but her family and protesters have accused the government of her murder.
The protests against her death have galvanised a wider demonstration against the restrictions on women's lives, and poses the biggest challenge to the Khamenei regime in years.
So could this popular revolt be a watershed moment for Iran?
Kathryn speaks to Golnaz Esfandiari, a senior correspondent for RFE/RL, focusing on Iran, and to Masih Alinejad, an Iranian journalist and activist, who now lives in exile - in an FBI safehouse, in the United States. She's the founder of several online movements, including #WhiteWednesdays, #MyCameraIsMyWeapon and #MyStealthyFreedom. With a large social media following back in Iran, she has helped galvanise the country's women to protest the hijab by encouraging them to post images of themselves defying the strict dress code laws and trashing their head coverings.