An expedition has set off from Uganda bidding to be the first to travel the entire length of the Nile by boat.
"It's the world's last challenge," said team leader Hendri Coetzee of the trip along the world's longest river which should end in four months' time.
The voyage, mostly by raft, aims to draw attention to the plight of people living along the Nile.
The team, which is sponsored by aid agency Care International, plans to visit humanitarian projects en route.
They also aim to highlight growing environmental threats to the Nile, which has hosted a huge variety of wildlife and plant species for many thousands of years.
Hazards abound
Beginning at the Bujagali Falls near Jinja, the 6,700 km (4,160 mile) trip through Uganda, Sudan and Egypt should end at the Mediterranean coast in May if all goes well.
The seven expedition members have all lived in East Africa for several years and have wide experience of travelling through the continent.
But conditions on the river and the war zones they have to travel through will test their skills to the limit. They will have to deal with rapids and keep an eye out for crocodiles, hippos and elephants.
Diseases such as malaria may also present problems, and the seventh team member is a doctor joining them for what promises to be a gruelling six-week slog through the swamps of southern Sudan.
In northern Uganda and southern Sudan they could come across various militias and rebel groups. Parts of northern Uganda have been terrorised for years by rebels of the Lord's Resistance Army, despite the government's avowed determination to root them out.