Burnt-out military vehicles, cars pockmarked with hundreds of bullet holes, and rusting tanks daubed with Arabic script litter the main roads in Nigeria's Adamawa State.

Nigeria's military has recaptured all of the major towns seized by the insurgents. Boko Haram's main fighting force is hemmed into the Sambisa Forest, where it is being pounded by air raids and attack helicopters.

Internally displaced people in Nigeria's northeast have started returning home, but health clinics, banks and schools are still lacking and vast stretches of farmland between towns stand barren, meaning thousands could face severe food shortages.

Reuters photographer Akintunde Akinleye visited former Boko Haram strongholds in north-eastern Nigeria. The insurgents have retreated, leaving Islamic teachings written on the walls of people's homes. Signs of Western education or Christianity have been crudely erased or destroyed.