Near MOSUL, Iraq — Hamid Merza Zorab throws his hands up in desperation as he surveys the ruins of his home, occupied by ISIS for more than two years and destroyed in the battle against the militants.

A crater in the ground is all that remains of the living room where the family once hosted neighbors and relatives for tea. Nearby, a crumbling stairway rises from the rubble, leading to nowhere. Darkening storm clouds gather above where the bedroom should have been.

“It belonged to my son,” says the 73-year-old, before suddenly turning away from the reporter to suppress a sob. “Day and night I remember him.”

Zorab’s family was one of a handful to return to the village after it was liberated from ISIS in the weeks leading up to the Mosul offensive.

Returning wasn’t a choice. Deprived of an income for more than two years, they couldn’t afford to live anywhere else.

Zorab was struggling to care for his family — 12 children and grandchildren — so his 40-year-old son, Muslah, agreed to help a neighbor move furniture in exchange for a few Iraqi dinars. After finishing the job, he and two other villagers went into the nearby mosque to wash their hands. They had no way of knowing that the faucet was wired to an ISIS booby-trap. All three died instantly.

These ISIS devices were found a few meters away from the village school. Lucy Kafanov / NBC News

Their story isn’t unusual. In areas surrounding Mosul and inside the city itself, retreating ISIS militants left behind thousands of homemade explosives, mines and booby traps. They are buried alongside roads, hidden in farm fields, scattered around schools and inside homes. Some have a military purpose and were intended to keep advancing Iraqi and Kurdish forces at bay. Others, simply made to kill.

“It’s mainly to catch civilians and people who are desperately trying to come home,” says Salaam Mohammed Amin, a Technical Field Manager for Mines Advisory Group (MAG), a non-profit that works to remove mines across the globe. “It’s the worst contamination I’ve ever seen in my entire lifetime — it’s unprecedented.”

On a recent afternoon, Salaam took NBC News on a tour of one of several villages currently being cleared by MAG. Some of homes remain intact while others were flattened in the fighting or by ISIS explosives.

Red-and-white tape marked out enormous live mines that protruded from the ground. A massive stockpile of home-made explosives, defused by MAG, was stacked against the wall of one of the homes. In the distance, near the village school, MAG demining experts were working to clear a vast militant minefield using metal detectors.

At least ten villagers were killed by ISIS booby-traps since the militants were ousted, and Salaam wants to make sure there aren’t any more casualties.

Women in the village receive life-saving lessons from Mines Advisory Group (MAG), including how to distinguish between the many types of deadly explosives left behind by ISIS. Lucy Kafanov / NBC News

“Some of the people here are desperate to get back to their homes even though the areas haven’t all been cleared,” he explains. “So we do our best to help them. But making this place completely safe will take time.”

On several occasions throughout the tour, Salaam is interrupted by villagers coming to greet him or to ask whether he would help clear their home of explosives. Some see him as the only hope for a return to normality. Others, like Zorab, treat him like family; it was Salaam who risked his life to enter the booby-trapped mosque to recover the body of Zorab’s son.

“We’ve become a part of the community, visiting with them every day, attending their funerals, getting to know their families,” Salaam says.

An Iraqi-Kurd with an infectious smile and thick moustache, Salaam has spent more than two decades with MAG working to defuse mines around the world. Having lived through the Iran-Iraq war of the 1980s and Saddam Hussein’s brutal repression of the Kurdish people, Salaam has seen first-hand the horror mines and unexploded ordinances can wreak on communities.

For him, the task is personal.

“I look at these people’s children like they are my children,” Salaam says. “That’s why we are there to save their lives … to support them, to send them back to school so they can have a brighter future.”

Over recent weeks, MAG has helped to clear hundreds of mines in the village recently visited by NBC News, but thousands more remain in the areas surrounding Mosul. IEDs have been used for decades but ISIS is now using them on a “quasi-industrial scale,” according to a report published by Conflict Armament Research (CAR), a private arms-tracking organization mandated by the European Union.

Salaam Mohammed Amin, from the global non-profit Mines Advisory Group (MAG), says the contaminationleft behind by ISIS in his home region of Iraq is the worst that he's seen anywhere in the world, Lucy Kafanov / NBC News

While Peshmerga forces and the Iraqi army have made efforts to clear some of the ISIS explosives left behind, there are few resources available to make villages and districts safe enough for residents to return.

ISIS explosives pose a particular challenge because of the unprecedented scale of production and because the militants have devised new weapons, which they’ve used against different targets. The militants had taken over Mosul’s plastics factories and nearby fertilizer production facilities in order to produce bombs in the thousands.

MAG International Communications Manager Sean Sutton describes the demining work as a "race against time."

“This is the front line of humanitarian intervention. These people have nothing, they’ve lost their animals, their livelihoods and they can’t rebuild their lives when there are explosives in the ground or hidden inside kitchen cupboards,” says Sutton. “They’ve survived the war, now they have to come back and find a way to survive the peace.”

Salaam greets a group of children who have gathered near a home for a safety lesson organized by MAG. Through games and pictures, the little ones are taught the different types of booby traps they might encounter in their village, instructing them in what to avoid and what not to touch.

After watching for a few minutes from a distance, Salaam sighs and makes his way over towards the minefield. There is work to be done, mines to defuse, lives to save.