Ghaith Abdul-Ahad travels deep into Yemen's radical heartland to investigate how Al Qaeda and affiliated militants have seized areas in southern Yemen and are winning some popular support.
One of the early roots of the film "Secret Daughter" was FRONTLINE's research into the growing debate over racial classification and the social phenomenon commonly known as "passing." Mario deValdes y Cocom, an historian of the African diaspora, researched some of history's more interesting examples of mixed racial heritage:
