Thousands who couldn't squeeze in listened outside in the surrounding streets.
All week, Iran's state media have been trying to convince people that the political unrest was incited by foreign plotters, including Americans, so we chose to observe from a quieter side street.
On the face of it, the Friday prayer ceremony is a religious occasion. But in spite of thousands of the devout who came to hear the Supreme Leader, everybody knows this is a pivotal political moment.
"The results of an election come from the ballot box - not the street," the Supreme Leader told the crowd.
He defended President Ahmadinejad's landslide win last Friday, saying, "Our system has no room for fraud."
Click below to watch all of CBS News correspondent Elizabeth Palmer's report from Iran.