Why has the tenth parallel turned into a frontline of conflict between Muslims and Christians?
It is the line of latitude 1,100 kilometres north of the equator where more than half of the world's Muslims and over 60 per cent of the world's Christians live.
Author and journalist Eliza Griswold spent seven years travelling through the fault lines of Nigeria, Sudan, Somalia, Indonesia, Malaysia and the Philippines trying to understand the origins and the reasons of this religious divide.
It is also the subject of her book, The Tenth Parallel, where she tells us the conflict is often about natural resources and land as much as it is about religion.
You can join the conversation. Watch this episode of Riz Khan live on Thursday, January 27, at 1930GMT. Repeats will air the next day at 0430GMT, 0830GMT and 1430GMT.
Source: Al Jazeera