More details have emerged about the charity motorcycle rally through South Africa Princes William and Harry are due to embark on later this month.
The adventure-loving siblings will traverse some of the most inhospitable terrain on the planet, and will sleep rough during the eight-day trek across 1,000 miles of mountain country.
"It's going to be one of the hardest and most demanding things they will ever have done in their lives," says the trip's organiser. "At times they will be sitting on their bikes looking up at a 60-degree slope wondering how… they are going to get up it. Not even realising there is a deep river crossing to get through on the other side."
Harry, who passed his motorbike test after taking an intensive course this summer, is said to be behind the idea of the African adventure fundraiser. Around 80 participants will take part, each pledging at least £1,500, to raise more than £300,000 for organisations including Sentebale, the charity Harry set up in memory of the Princes' mum, and the Nelson Mandela Children's Fund.