23 February 2015
Children as young as seven are leaving their homes in Africa to travel thousands of miles alone, across land and sea, to Europe.
More lone children than ever before are attempting the route, some sent by their parents who do not want them to grow up in repressive countries.
One of the busiest and most dangerous routes begins in Eritrea, where they cross the border into Sudan.
Paul Kenyon visited one of the first stepping stones on this route, Shagarab refugee camp in Sudan.
Panorama: Children of the Great Migration, Monday 23 February, 20:30 GMT, BBC One. It will be on BBC World on Saturday 28 February.