Large crowds of protesters marched through Iran’s capital Tehran and several other major cities on Thursday evening, marking what observers describe as the biggest show of force by opponents of the clerical establishment in years, according to verified videos and rights groups.Footage verified by BBC Persian showed peaceful demonstrations in Tehran and the northeastern city of Mashhad, where protesters were not immediately dispersed by security forces. Later in the night, internet monitoring groups reported a nationwide internet blackout, further restricting the flow of information from the country.In the videos, protesters were heard chanting slogans calling for the overthrow of Supreme Leader Ayatollah Ali Khamenei and the return of Reza Pahlavi, the exiled son of Iran’s last shah, who had urged supporters to take to the streets.The demonstrations marked the 12th consecutive day of unrest, triggered by public anger over the collapse of the Iranian currency. According to human rights groups, ...