The Taliban have staged devastating attacks in the capital of Afghanistan, Kabul, in recent weeks. And a BBC study has discovered the group is active across the majority of the country – pushing beyond its traditional southern stronghold into eastern, western and northern parts. Seventeen years after the Taliban were toppled by a US-led invasion, it is clear the insurgent group has not been defeated. Why are the Taliban so resilient?

Presenter: Helena Merriman Producers: Ruth Alexander and Josephine Casserly