Yemen's ancient city where people escape civil war

It’s been four years since an Arab military coalition, led by Saudi Arabia, intervened in Yemen’s civil war.

Tens of thousands have been killed, but in amongst the conflict there is one place that’s prospering – the city of Marib.

How is that possible? The BBC’s Paul Adams went to find out.

Producer: Maria Byrne; Camera: Moose Campbell; Editing: Olivia Lace-Evans