Africa on BBC Knowledge: final episode airing on 17 March

A Barbary macaque, its kind were separated from their ancestors in the south when the Sahara first formed, and are now trapped in the snow-capped Atlas Mountains. © Tom Thurston

Two male Grevy's zebra rear up on their hind legs in an attempt to dominate one another. Grevy's zebra are the largest of the zebras and are supremely adapted to desert living. They fight to defend territory and for access to females, who wander the land in search of males. © BBC 2012

The snow-capped Atlas Mountains seen from the edge of the Sahara desert. Within the last 10 000 years, a subtle change in the Earth'??s orbit precipitated dramatic change in north Africa â?? an apocalypse that turned the land into the desert it is today. But the very tops of the Atlas Mountains, seen on the horizon, were high enough to escape the disaster. © BBC 2012

Deep snow covers cedar trees, a rare image of north Africa. The Sahara has been a desert for less than 10 000 years. A shift in the climate caused a rapid and catastrophic transformation in the north of the continent. Savannah turned to dust, lakes dried out and forests fell â?? except this one, an island in the sky on the slopes of the Atlas Mountains. © Matthew Wright

A Barbary macaque, clutching its infant, is perched in a cedar tree high in the Atlas Mountains in mid winter. Much of north Africa including the Sahara was once forested and this small patch is one of only a few areas that remain. © Matthew Wright

Libya's Sand Sea; 1 000 000 square kilometres of exquisitely sculpted banks of sand, is one of the hardest places on Earth for life to survive. As wind stirs the sand grains the dunes begin to 'sing'. © Ian Llewellyn

Snow covered plateau in the Atlas Mountains - the north of this continent is dominated by the Sahara desert so images like this are rare. The team returned to this corner of Africa three times to try to film falling snow. © Matthew Wright

Monkeys are a familiar sight in Africa, snow on the other hand... Barbary macaques live within sight of the searing hot, Sahara desert but are trapped high in the ice-cold Atlas mountains. Their ancestors escaped hardship of one kind only to face another. © Tom Thurston

The camel is the only pack animal able to withstand the rigours of the Sahara. But since a monumental shift in the Earth's climate caused the formation of the desert, and its expansion year on year, camels have had to walk further, much further, between sources of water. © Katrina Bartlam

The White Desert in Egypt is dominated by strange formations, ancient coral reefs carved and shaped by wind blown sand. © Rupert Barrington

A dung beetle rolling a ball of camel dung. The Sahara is perhaps the most challenging environment for these beetles to survive on the continent. A rare dung pile, left by travelling camels, might be the only chance a beetle has to provide food for their young. But the hot sand and burning sun turn the dung roll into a race against time, with the odds stacked against the beetle. © Katrina Bartlam