Levison Wood sets out to walk the length of the River Nile from source to sea; his nine-month, seven-million-step journey takes him through jungles, savannah, deserts, cities and war zones in some of Africa's most remote and spectacular locations.

Lev and his guide Boston are 1100 miles and four months into their journey, in the world's newest nation, South Sudan; arriving in the capital, Juba, Lev and Boston are arrested by secret police.

Five months and more than 2000 miles into his journey, Lev is in Sudan, facing his biggest physical obstacle yet: the Sahara desert; he has to walk 1300 miles across one of the most inhospitable places on Earth.

After seven months walking, Lev reaches his final country: Egypt; he has 900 miles to go to the Mediterranean but the authorities give him just 45 days to finish.