Among the speakers at Saturday's rally was journalist Roxana Saberi, who was jailed in Iran for three months earlier in the year.
"Why are we speaking out? Because we know that remaining silent won't help those Iranians who are being wronged. Maybe because we know that what happens in Iran today will not only effect its roughly 70 million people, but also generations of Iranians to come," Saberi said to those gathered.
More than 100 similar rallies were held worldwide Saturday in what organizers called a global day of action and solidarity. The rallies were backed by international watchdog groups Human Rights Watch and Amnesty International.