Pope Benedict XVI waves from his popemobile as he arrives to lead a mass at the Cuatro Vientos aerodrome as part of World Youth Day festivities in Madrid August 21 2011. REUTERS/Andrea Comas (SPAIN - Tags: SOCIETY RELIGION)
Pope Benedict XVI arrives to celebrate a mass at the Cuatro Vientos air base outside Madrid during the World Youth Day (WYD) festivities on August 21, 2011. The pilgrims spent the night in the open air at the base of Cuatro Vientos, eight kilometres (five miles) southwest of Madrid, where Benedict is to celebrate the closing mass of the August 16-21 youth festival on Sunday morning. AFP PHOTO / RAFA RIVAS
Pope Benedict XVI arrives on his Popemobile to celebrate a mass at the Cuatro Vientos air base outside Madrid during the World Youth Day (WYD) festivities on August 21, 2011. The pilgrims spent the night in the open air at the base of Cuatro Vientos, eight kilometres (five miles) southwest of Madrid, where Benedict is to celebrate the closing mass of the August 16-21 youth festival on Sunday morning. AFP PHOTO / RAFA RIVAS