Harley-Davidson motorcycle riders park their bikes in the Via della Conciliazione leading to the Vatican (seen at left) as they wait for Pope Francis to drive by to bless them ahead of Mass in St. Peter's Square on Sunday, June 16, 2013, in Rome. The riders are gathered in the Eternal City for a four-day event to celebrate the motorcycle company's 110th anniversary. (AP Photo/Andrew Medichini)

Photo by: Andrew Medichini

Harley-Davidson motorcycle riders park their bikes in the Via della Conciliazione leading to the Vatican (seen at left) as they wait for Pope Francis to drive by to bless them ahead of Mass in St. Peter's Square on Sunday, June 16, 2013, in Rome. The riders are gathered in the Eternal City for a four-day event to celebrate the motorcycle company's 110th anniversary. (AP Photo/Andrew Medichini)