When Ziba Murat last spoke to her mother, the older woman urged her to "sleep when the baby sleeps." Murat's daughter was then just 3 months old, and Murat, like many new parents, was struggling to get enough rest. Nearly three years on from that phone conversation, Murat still doesn't sleep well, but, most nights, it has nothing to do with her daughter. She often lies awake worrying about her mother, who is one of millions of Uyghur Muslims who have been detained by the Chinese government in the past few years.