The Save Darfur Rally to Stop Genocide featured dozens of speakers, including actor George Clooney, Olympic speed skating medalist Joey Cheek and numerous politicians and religious leaders from across the ideological spectrum -- from the liberal Rev. Al Sharpton to the conservative Rev. Richard Land.
Clooney's father, longtime journalist Nick Clooney, told the crowd the first order of business is to establish some protection for people in Darfur.
"Nothing we can do will help if they're dead," he said. "And they're dying every day."
Cheek called on Americans to put pressure on political leaders and the media to do more to stop the genocide.
"Just having a rally is not going to stop people being killed," he said.
The conflict in Darfur has created at least 2 million refugees and left at least 180,000 -- and perhaps as many as 300,000 -- people dead.