Dave Grohl of Foo Fighters performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Dave Grohl of Foo Fighters performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
July 4, 2015 - Nate Mendel and Dave Grohl of the Foo Fighters perform at the Foo Fighters 20th Anniversary Blowout at RFK Stadium in Washington, D.C....
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
July 4, 2015 - Rock and Roll Hall of Fame inducteeBuddy Guy performs at the Foo Fighters 20th Anniversary Blowout at RFK Stadium in Washington, D.C.
July 4, 2015 - Trouble Funk performs at the Foo Fighters 20th Anniversary Blowout at RFK Stadium in Washington, D.C.
July 4, 2015 - Dave Grohl of the Foo Fighters performs on a mobile "throne" at the Foo Fighters 20th Anniversary Blowout at RFK Stadium in...
Musician Gary Clark Jr. Poses backstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Big Tony Fisher and Timothius "Tee-Bone" David of Trouble Funk perform onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on...
Trouble Funk performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Taylor Hawkins of Foo Fighters performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Buddy Guy performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Musician Ann Wilson of Heart poses backstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson and Ann Wilson of Heart appear backstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington,...
Musician Gary Clark Jr. Appears backstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Gary Clark Jr. Performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Cool J performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson and Ann Wilson of Heart perform onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington,...
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Nancy Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Ann Wilson of Heart performs onstage during the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.
Fans attend the Foo Fighters 20th Anniversary Blowout at RFK Stadium on July 4, 2015 in Washington, DC.