The crowd cheers as Monsignor Georg Gaenswein, left, puts a Mexican sombrero on Pope Benedict's XVI head as they arrive in  Parque del Bicentenario to celebrate a Sunday Mass. (AP Photo/Gregorio Borgia)

Photo by: Gregorio Borgia

The crowd cheers as Monsignor Georg Gaenswein, left, puts a Mexican sombrero on Pope Benedict's XVI head as they arrive in Parque del Bicentenario to celebrate a Sunday Mass. (AP Photo/Gregorio Borgia)