Mahmoud Ahmadinejad faces a critical challenge to his leadership from his moderate rival Mir Hossein Mousavi. The relaxation of standards leading up to today's election has given rise to a movement which just may topple the repressive regime of Ahmadinejad. At least that's what the Greens (Sabz) hope will happen. Among the more startling aspects to this election has been the prominent role of Mousavi's wife, Zahra Rahnavard, an Iranian artist and political scientist who served as the chancellor of Alzahra University in Tehran. The role of younger Iranians, especially women, and harnessing the power of new technologies have also been crucial factors in Mousavi's rise, just as it was with Barack Obama.

Ian Black of The Guardian reports on the tremendous excitement in Tehran.