Rare access to former Boko Haram-held towns in Nigeria

Over the past six years, the violence in north-east Nigeria has been relentless - from the capturing of the Chibok schoolgirls to the razing of entire towns.

Boko Haram militants have seemed unstoppable.

Now military forces from Nigeria, Cameroon, Chad and Niger have been taking back towns lost to Boko Haram.

It has been a dangerous and difficult area to report on, but the BBC's Tomi Oladipo has gained rare access to the region.