Hundreds of thousands are now marching in the streets of Iran against the election results. They're headed toward Revolution Square, perhaps literally.

UPDATE: The BBC is now saying the rally was 1-2 million. The video above was from earlier. The picture below was from later today when the crowds really began to swell.

(Sky News) Tens of thousands of supporters of Iran's opposition leader, Mir Hossein Mousavi, have defied a ban to attend a rally in Tehran after Mahmoud Ahmadinejad won a landslide victory in the presidential elections. Sky's Tim Marshall reports