The Black Keys performs at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
The Black Keys performs at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
The Black Keys performs at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
Mayor Rahm Emanuel introduces The Black Keys at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
Ozzy Osbourne of Black Sabbath performs at Lollapalooza on Friday, Aug. 3, 2012. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans cheer as Black Sabbath performs at Lollapalooza on Friday, Aug. 3, 2012. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Ozzy Osbourne of Black Sabbath performs at Lollapalooza on Friday, Aug. 3, 2012. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
A fan uses a lighted hula hoop as Ozzy Osbourne and Black Sabbath perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans cheer as Ozzy Osbourne and Black Sabbath perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
M83 performs at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
M83 performs at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Fans crowd surf during Passion Pit's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Passion Pit performs at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Fans crowd surf during Passion Pit's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Passion Pit performs at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans crowd surf during Passion Pit's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans enjoy Passion Pit's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans enjoy Passion Pit's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Die Antwoord performs at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brock Brake/RedEye, Aug. 3, 2012
Die Antwoord performs at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brock Brake/RedEye, Aug. 3, 2012
Die Antwoord performs at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brock Brake/RedEye, Aug. 3, 2012
Concert goer's wait for M83 to perform at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Concert goer's cheer during Passion Pit's performance at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
A concert goer gets pulled by security before Passion Pit's performance at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
A concert goer receives help from security before Passion Pit's performance at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Fans receive water from security during Madeon's performance at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
James Mercer of The Shins performs at Lollapalooza on Friday, Aug. 3, 2012 — Mike Rich/RedEye, Aug. 3, 2012
A fan chugs a beer at Perry's stage during Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans press toward the stage while Madeon performs at the Perry's stage during Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans press toward the stage while Madeon performs at the Perry's stage during Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans press toward the stage while Madeon performs at the Perry's stage during Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans dance to Madeon at the Perry's stage during Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Sharon Van Etten performs at Lollapalooza on Friday, Aug. 3, 2012. — Mike Rich/RedEye, Aug. 3, 2012
Sharon Van Etten performs at Lollapalooza on Friday, Aug. 3, 2012. — Mike Rich/RedEye, Aug. 3, 2012
Blind Pilot performs at Lollapalooza on Friday, Aug. 3, 2012. — Mike Rich/RedEye, Aug. 3, 2012
Blind Pilot performs at Lollapalooza on Friday, Aug. 3, 2012. — Mike Rich/RedEye, Aug. 3, 2012
Fans listen to Dry the River perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans listen to Dry the River perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans listen to Dry the River perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans videotape Dry the River's performance at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Dry the River performs at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans listen to Dry the River perform at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Music fans walk between stages at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Fans try to beat the heat at Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Security fences surround Lollapalooza on Friday, Aug. 3, 2012 in Grant Park. — Brian Cassella/Chicago Tribune, Aug. 3, 2012
Haley Reinhart performs at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
Fans cheer during Michael Kiwanuka performance at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Michael Kiwanuka peforms at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Sara Cohen takes a break from the heat near a fan at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Totally Enormous Extinct Dinosaurs performs at Lollapalooza on Friday, Aug. 3, 2012. — Brock Brake/RedEye, Aug. 3, 2012
Concert goers walk down Columbus drive during Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
Concert goers walk aross Grant Park towards the Red Bull stage at Lollapalooza Friday August 3, 2012. — Armando L. Sanchez/Chicago Tribune, Aug. 3, 2012
