Help Pick America's Most Promising Urban Innovation

305 cities representing more than 64 million Americans applied for the Bloomberg Philanthropies Mayor's Challenge, a competition encouraging local governments to innovate in their communities.

20 finalists have emerged from the fray, and the Huffington Post and Bloomberg Philanthropies have launched an online platform, the Mayor's Challenge Fan Favorite, for citizens across the country to view video proposals from 20 mayors and select "the civic innovation Americans most want to see succeed," write Michael Bloomberg and Arianna Huffington.

Bloomberg and Huffington hope that opening up the competition to a popular vote will energize citizen-led discussions about local solutions to urban challenges and spur the effort to implement some of the proposals the finalists have put forth.