Residents line up in the rain at a mobile nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

Residents line up in the rain at a makeshift nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

Residents line up in the rain at a makeshift nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

Residents holding umbrellas line up in the rain at a makeshift nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

Security personnel in raincoats keep watch as people line up in the rain at a makeshift nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

Security personnel in raincoats keep watch as people line up in the rain at a makeshift nucleic acid testing site amid a mass testing for the coronavirus disease (COVID-19) in Chaoyang district of Beijing, China April 27, 2022. REUTERS/Carlos Garcia Rawlins 

An acid container (in orange) lies among debris in a flooded area at Chanaral town in Chile April 8, 2015. The death toll from heavy rains and flooding that battered Chile last week has risen to 29, with another 150 still missing, according to authorities. REUTERS/Ivan Alvarado 

A view of the White House as it rains in Washington December 6, 2014. U.S. President Barack Obama, who had medical tests on Saturday after complaining of a sore throat, is suffering from acid reflux, the president's physician said. REUTERS/Joshua Roberts (UNITED STATES - Tags: POLITICS HEALTH) 

A view of the White House as it rains in Washington December 6, 2014. U.S. President Barack Obama, who had medical tests on Saturday after complaining of a sore throat, is suffering from acid reflux, the president's physician said. REUTERS/Joshua Roberts (UNITED STATES - Tags: POLITICS HEALTH) 

Cardinal Timothy Dolan stands in St. Patrick's Cathedral while watching the 251st annual St. Patrick's Day Parade in New York March 17, 2012. Saint Patrick's Cathedral, New York City's iconic house of worship on Fifth Avenue, is getting a facelift. The $175 million restoration will take about five years and will include what church officials described as a thorough scrubbing: its 1,300 panels of stained glass will get protective glazing, pipes from its massive organ will be cleaned and acid rain and other deposits will be wiped away. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY RELIGION ANNIVERSARY) 

Pope Benedict XVI waves from his Pope Mobile as he arrives for a Vespers service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION TPX IMAGES OF THE DAY) 

Pope Benedict XVI waves from his Pope Mobile as he arrives for a Vespers service for young people at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION HEADSHOT) 

Pope Benedict XVI arrives in his Pope Mobile for a Vespers service for young people at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI arrives for a Vespers service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI arrives for a Vespers service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI waves from his Pope Mobile as he arrives for a Vespers service with young people in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI holds a service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI holds a service for young people at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI holds a Vespers service for young people at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI holds a service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Faithful hold candles during a Vespers service of Pope Benedict XVI at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Faithful hold candles during a Vespers service of Pope Benedict XVI at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Faithful light candles during a Vespers service of Pope Benedict XVI at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

A pilgrim holds up a candle in front of a large screen showing Pope Benedict XVI as he conducts a Vespers service with young people at the fairground in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI is presented a framed photograph during a meeting with the Presidium of the Central Committee of German Catholics (ZdK) at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI and Archbishop Robert Zollitsch meet with Lois Glueck (R) President of the Central Committee of German Catholics (ZdK) at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI shakes hands with Stefan Vesper (R) during a meeting with the Presidium of the Central Committee of German Catholics (ZdK) at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI, sits next to Vatican Secretary of State Cardinal Tarcisio Bertone (3rd R) and Archbishop Robert Zollitsch (L) during a meeting with seminarians at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI, sits next to Vatican Secretary of State Cardinal Tarcisio Bertone (R) and Archbishop Robert Zollitsch during a meeting with seminarians at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Faithful light candles during a Vespers service of Pope Benedict XVI at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Faithful hold candles during a Vespers service of Pope Benedict XVI at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI visits the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI arrives in his Pope Mobile for a Vespers service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI arrives for a Vespers service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI holds a Vespers service with young people at the fairground in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI arrives in his Pope Mobile for a service at the fairground in the south-western German town of Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI waves from his Pope Mobile as he arrives for a Vespers service with young people in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI waves to the faithful from his Pope Mobile as he arrives for a Vespers service with young people in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Max Rossi (GERMANY - Tags: RELIGION POLITICS)

Faithful cheer as they await the arrival of Pope Benedict XVI for a Vespers service Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Miro Kuzmanovic (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI waves to the faithful from his Pope Mobile as he arrives for a Vespers service in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Max Rossi (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI waves to the faithful from his Pope Mobile as he arrives for a Vespers service in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Arnd Wiegmann (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI prays at the chapel of the seminary in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Wolfgang Radtke (GERMANY - Tags: RELIGION POLITICS)

Faithful await the arrival of Pope Benedict XVI for a Vespers service in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Max Rossi (GERMANY - Tags: RELIGION POLITICS)

Faithful await the arrival of Pope Benedict XVI for a Vespers service in Freiburg September 24, 2011. Pope Benedict straddled his homeland's religious and geographic divisions on Saturday, praising the faithful for enduring communism's "acid rain" effect in former East Germany and then addressing cheering Catholic crowds in the west. REUTERS/Max Rossi (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI meets with former German chancellor Helmut Kohl at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Arnd Wiegmann (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI meets with former German Chancellor Helmut Kohl and his wife Maike Kohl-Richter at the seminary in Freiburg September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism. The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Wolfgang Radtke/Pool (GERMANY - Tags: RELIGION POLITICS)

Pope Benedict XVI waves to the crowd from inside his popemobile as he arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland/Pool (GERMANY - Tags: POLITICS RELIGION)

The popemobile with Pope Benedict XVI drives along the main shopping street of Freiburg, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Michael Probst/Pool (GERMANY - Tags: POLITICS RELIGION) 

Pope Benedict XVI waves to the crowd from inside his popemobile as he arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland/Pool (GERMANY - Tags: POLITICS RELIGION)

The popemobile with Pope Benedict XVI drives along the main shopping street of Freiburg, September 24, 2011, with the Martinstor city gate pictured in background. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Michael Probst/Pool (GERMANY - Tags: POLITICS RELIGION)

Pope Benedict XVI arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland (GERMANY - Tags: POLITICS RELIGION HEADSHOT)

Pope Benedict XVI waves to the crowd from inside his popemobile as he arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland/Pool (GERMANY - Tags: POLITICS RELIGION)

Pope Benedict XVI arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland/Pool (GERMANY - Tags: POLITICS RELIGION)

Pope Benedict XVI waves to the crowd from inside his popemobile as he arrives to visit the Freiburg Cathedral, September 24, 2011. Pope Benedict has praised Catholics in eastern Germany who held on to their Christian beliefs despite the "acid rain" that corroded their faith under the Nazis and communism.The Bavarian-born pontiff is on a four-day visit to Germany, his third visit to his homeland since he took over as head of the Catholic church. REUTERS/Daniel Roland/Pool (GERMANY - Tags: POLITICS RELIGION)