Earth Day on the National Mall (22 images)

Fans cheer as the Flaming Lips perform during the Earth Day on the Mall concert on the National Mall in Washington on April 19, 2009. (UPI Photo/Kevin Dietsch)

Wayne Coyne, of the Flaming Lips, performs during the Earth Day on the Mall concert on the National Mall in Washington on April 19, 2009. (UPI Photo/Kevin Dietsch)

Actress Joy Bryant speaks during the Earth Day on the Mall concert on the National Mall in Washington on April 19, 2009. (UPI Photo/Kevin Dietsch)

An attendee rides a bike that powers a light bulb at the Earth Day on the Mall concert on the National Mall in Washington on April 19, 2009. (UPI Photo/Kevin Dietsch)