Harley-Davidson motorbike riders were in St Peter's Square in Rome on Sunday to join pilgrims for a Mass and a blessing by Pope Francis.
"I greet the many participants in the Harley-Davidson motorcycle assembly," the pope said during his weekly Angelus prayer.
The bikers are marking the 110th anniversary of Harley-Davidson.
An estimated 35,000 Harley-Davidson riders are in Rome for the event, attending concerts and taking part in a parade.
On Wednesday, the US manufacturer of the bikes gave the pope two white classic Harleys for the Vatican police force to use.