British Princes William and Harry set off Saturday on a grueling 1,000-mile motorcycle rally in South Africa to raise money for charity.
The pair joked that they had a wager on which royal tumbles from his bike the most during the eight-day off-road adventure.
"It's going to be very challenging and we're expecting to fall off many a time," said Harry, 24, before more than 80 riders set off from the holiday resort of Port Edward on South Africa's southeast coast.
A crowd cheered the riders as they hit the winding dust road bound for the southern coastal city of Port Elizabeth.
William, 26, who next year will begin training to be a Royal Air Force search-and-rescue helicopter pilot, said he and his brother had decided to take part in the rally "because it's a mixture of adventure and charity."
Funds raised through the princes' participation in the Enduro Africa 08 event will be divided among UNICEF, the Nelson Mandela Children's Fund and Sentebale, a charity established by Harry to help disadvantaged children in Lesotho.