[BBC] It is thought that more than ten million girls around the world are married before they turn 18.

The effect on their health and education can be catastrophic.

Two of Africa's best known elders are campaigning to end the practice; Nelson Mandela's widow Graca Machel - who has just ended her official period of mourning - and Archbishop Desmond Tutu.

Nomsa Maseko spoke to them both in a video interview available here.