Lagos, Nigeria (CNN)Terror group Boko Haram has kidnapp
UNICEF: Boko Haram has kidnapped more than 1000 children in Nigeria
Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
Under Operation "Lafiya Dole" -- meaning "peace by any means" in Hausa -- the Nigerian army is working under intense scrutiny to locate and return the stolen Chibok girls to their parents.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
Boko Haram's violent footprint is evident across the vast expanse of Nigeria's northeast, where village after village has been left devastated by the group's fighters.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
What Boko Haram couldn't loot, it burned to the ground. To this day, people remain afraid to return home.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
Frequent attacks from Islamic insurgents have prompted residents to flee their villages and head to Maidugiri where it is, to an extent, safer.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
The city of Maidugiri is at the heart of the military's campaign. Something of a safe haven for many fleeing Boko Haram, it has become an oasis in northeastern Nigeria, where around 2.5 million displaced people now reside.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
The region's soft sand is ideal for hiding improvised explosive devices, or IEDs. This means the military must travel in heavily armored convoys with mine-proof trucks providing protection from the front.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
Empty ammunition cases litter the ground, untouched since they flew from the machine guns used in a skirmish between the Nigerian army and Boko Haram fighters.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
The operation's "theater commander" Maj. Gen. Leo Irabor tells CNN that while he is proud of his men's achievements in pushing back Boko Haram, they are in need of more international support to quash the insurgents.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
A vehicle full of troops scans the horizon scouting for any indication of insurgent presence.
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Photos: Penetrating Boko Haram's stronghold: The Sambisa Forest
The terrain in the northeast is unforgiving and troops face dehydration in the blistering heat while on patrol.
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