Paul McCartney's Mother's Day Free Concert At Zocalo.

General view of concert of Sir Paul McCartney at the Zocalo Square in Mexico City, on May 10, 2012. The concert was free and the authorities accounted around 90,000 people. AFP PHOTO / Antonio Nava (Photo credit should read ANTONIO NAVA/AFP/GettyImages)

Paul McCartney's Mother's Day Free Concert At Zocalo.

General view of concert of Sir Paul McCartney at the Zocalo Square in Mexico City, on May 10, 2012. The concert was free and the authorities accounted around 90,000 people. AFP PHOTO/Antonio Nava (Photo credit should read ANTONIO NAVA/AFP/GettyImages)

Paul McCartney's Mother's Day Free Concert At Zocalo.

General view of concert of Sir Paul McCartney at the Zocalo Square in Mexico City, on May 10, 2012. The concert was free and the authorities accounted around 90,000 people. AFP PHOTO/Antonio Nava (Photo credit should read ANTONIO NAVA/AFP/GettyImages)

Paul McCartney's Mother's Day Free Concert At Zocalo.

ANTONIO NAVA/AFP/GettyImages

General view of concert of Sir Paul McCartney at the Zocalo Square in Mexico City, on May 10, 2012. The concert was free and the authorities accounted around 90,000 people. AFP PHOTO/Antonio Nava (Photo credit should read ANTONIO NAVA/AFP/GettyImages)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: Paul McCartney performs during a free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)

Paul McCartney's Mother's Day Free Concert At Zocalo.

MEXICO CITY, MEXICO - MAY 10: A view of atmosphere during Paul McCartney's free Mother's Day concert at the Zocalo on May 10, 2012 in Mexico City, Mexico (Photo by Daniel Aguilar/Getty Images)