This is part of CNET's Road Trip 2017 summer series "The Smartest Stuff," about how innovators are thinking up new ways to make you — and the world around you — smarter.

It's still dark when the men arrive for work. At the outdoor base where they've gathered, the only light is the dying glow of a campfire at a guard post near the back. A night watchman rubs his hands over the embers to fend off the cold. The crow of a rooster tells us it's 5 a.m. here in Cuito Cuanavale, a small town in southern Angola, about 750 miles from the capital, Luanda. It's in a region so remote it's known as "the land at the end of the world."

The men, wearing hoods and beanies, line up in six rows of eight, like soldiers at attention. But instead of marching off to war, they are preparing to, in a way, do the exact opposite: clear away some of the up to 1 million land mines that have paralyzed Angola since its civil war ended in 2002. The morning ritual is known as the "parade." It's a reveille for the guys to gather for briefings and announcements before they head off to their assigned minefields to find and dig up explosives.

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Today is no ordinary day. It's the last day of demining in Cuito Cuanavale, which has been called the most densely mine filled town in Africa. But the demining isn't ending because the job is finished. Far from it. It's ending because a cut in funding is shutting down operations in the area, leaving as many as 35,000 mines still unearthed.

In Angola, everyone knows someone who's been killed or maimed by a land mine. James Martin/CNET

"Bom dia," says Ralph Legg, greeting the deminers in Portuguese, the local language. Legg, a tall and gangly Brit, is a location manager for the Halo Trust, a UK-based nongovernmental organization tasked with clearing the mines.

"Unfortunately, it's a sad day," says Legg, addressing the workers in English as one of his colleagues translates into Portuguese. "But please, as you always do, remain safe."

It's as quiet as a church service and just as solemn. Not only does the operation shutdown mean the land mines will stay buried, continuing to menace the local villagers, it also means all 86 deminers and staff in the area will lose their jobs.

With the land mines still there, Angola can't escape the shadow of its 27-year civil war. Land can't be cultivated for crops. Houses can't be built and villages can't expand. The mines, which come from at least 22 countries including Russia and the United States, block paths to schools and hospitals.

In Angola, on the western coast of southern Africa, there are an estimated 88,000 survivors of land mine accidents, though the number of people killed is unknown. Worldwide, the land mine death toll was almost 6,500 in 2015, a 10-year high and a 75 percent surge from the year before. In late June, CNET traveled to Angola to witness the situation firsthand.

Clearing mines is a painstakingly low-tech affair. Tools of the trade include a metal detector, a weed wacker and a meter-long stick. But NGOs are also looking to tech titans like Google for help. Demining teams survey minefields using satellite images from the search giant's Google Earth software — and put in a direct call to Google when those images aren't good enough. To scope out smaller areas, they also use drones.

Researchers are also seeking silver bullets: trained rats, "sniffer" bees and spinach that changes color when it detects a chemical in land mines. Still, most insiders insist that the old-fashioned method of boots on the ground is most effective.

It's been 20 years since Princess Diana, outfitted in a protective visor and vest, walked through an Angolan minefield with Halo to bring the matter to the world's attention. It was one of the last high-profile things she did in 1997, before her tragic death a few months later.

Now the global community has a new target. Landmine Free 2025, a campaign championed by Diana's son Prince Harry, calls for every country on the planet to be rid of land mines by that year. Many people doing the actual work are pessimistic about the timeline, and a setback like Cuito Cuanavale's stoppage doesn't help.

Back at the base, the scene is bustling as the morning sun peeks out. Supervisors and team leaders are sorting through maps of minefields. Other workers gather up equipment to load the cars. Some jump into Land Rovers parked along the perimeter of the base. The rest hop onto the bed of a massive tractor and rumble away.

They've got one more day of deadly work ahead of them.

One of the world's most dangerous minefields

"What are your blood types?" Legg asks matter of factly. We've arrived at a minefield in Cuito Cuanavale to see the deminers in action on their last day, and Legg says he needs to log us in.

Sure enough, there's a blank space on the sign-in sheet for blood type.

We laugh nervously.

It took us three days to get to Cuito Cuanavale. More specifically, 30 hours of flying from San Francisco to Huambo, Angola's second-largest city, and a bumpy 10-hour drive deep into the south of the country. On our way there, Legg, our de facto tour guide, told us, "You're going to one of the most dangerous minefields in the world."

Before we enter, we put on our safety gear. First, the body armor: A thickly padded vest covers your entire torso, and a flap shields your groin. In case of a blast, it's supposed to protect every major organ. If you think you've got it on tight enough, someone will come around and strap it on tighter, proving you, and the wind in your stomach, wrong.

Then, the visor: A clear plastic shield flips up like a welder's mask. It reaches below your chin so when you look down, it creates a protective seal over your neck.

This land mine once had a trip wire that, when snagged, would detonate the explosive. James Martin/CNET

After that, we get a formal safety briefing. The rules are common sense: no running, throwing objects or smoking in a minefield. Don't touch anything. "If unfortunately during your visit you hear an uncontrolled explosion, be calm, don't move, and wait for instructions," says Jose Antonio, a stocky Angolan with kind, wide set eyes, who heads up Halo's operations in the province. "You'll be conducted to a safe area."

With that, we walk into the minefield.

Along the path, red signs with skulls and crossbones printed on them tell us we're close to mines. It's an odd sensation — your heart rate speeds up and you become hyperaware of your steps. The snap of a twig can make your stomach jump.

And yet, it's a peculiar combination of anxiety and calm. While there are deadly bombs all around, the environs are physically beautiful. It's wooded and serene, almost idyllic. Deminers are working throughout the field. It's almost completely quiet, except for the faint rustling of steps and the whistle of a metal detector every few minutes.

Color-coded sticks are everywhere. Sticks with tips painted red cordon off dangerous areas. White-tipped sticks indicate that a land mine was once at that exact spot. When we look around, there are rows and rows of white sticks. In this minefield, 420 mines have been removed.

We come to our first mine. It's in a small hole about a foot deep. Only the edge of it is exposed, like some sort of deadly fossil. This one is an antitank mine, meant to destroy vehicles. Specifically, it's a TM-62 — a thick, round disc, like a giant bench press weight.

More than 70 types of mines were buried in Angola. That includes the PP-MISR, a terrifying Czechoslovakian mine that, when detonated, jumps chest high and sprays metal fragments. Its kill radius is more than 65 feet. Then there's the Soviet-made PMD-6, a small wooden box with a hinged lid slightly ajar. Stepping on the lid activates the detonator.

From the staging area, we review the safety standards and put on protective gear including chest pads and face masks, which must be work at all times. Rows of red-tipped sticks mark the boundary between the safe path, and the deadly, uncleared land. James Martin/CNET

We see only the side of the TM-62 mine because digging right above it would set it off. When a deminer excavates a mine, he creates a small trench just in front of where he thinks the land mine is. Then he scrapes away with a small shovel until he lightly touches the side of the mine.

To remove a land mine, the deminers set up a small charge right next to the mine and blow it up from a safe distance.

After we walk through that minefield, we drive to another one across the river. This one is more densely forested. It also has more menacing mines, including the PP-MISR, the jumping, metal-spitting one. While we're there, we see one in the ground. "If one of these went off, we'd all be killed," says Legg.

To work in this minefield, you need even-more-powerful gear. Unlike the standard protective vests, the ones worn here cover both your back and front, and reach to your knees. Instead of a regular visor, you wear a heavy black helmet with the visor attached.

"The work we do is quite scary," Abel Kavindama, a 36-year-old deminer, says through a translator as he leaves the minefield at the end of the workday. Tomorrow he'll be laid off. "We're looking for mines, and we don't know where they are."

"Don't be worried about the snakes. Worry about the minefields."

If you plug in the route from Huambo to Cuito Cuanavale into Google Maps, your first two turn-by-turn directions will be to just "drive." No street names. Eventually you'll get there "via unnamed roads." We embark on our 10-hour drive to the minefields with Legg and our Angolan driver, named Avelino, in an armored Land Rover with two gas tanks.

Red-tipped sticks stake out a boundary between safe ground and live land mines. James Martin/CNET

Land mines, once a common weapon of war, are buried from Cambodia to Colombia to Afghanistan. Estimates reach as high as 110 million worldwide. They come in all shapes and sizes. Antitank mines are big and sturdy, while antipersonnel mines, which target people instead of vehicles, are smaller and more sensitive.

In Angola, the problem dates back to 1975, when the country gained independence from Portugal. Two of the major liberation factions raged over who would run the newly freed nation. It boiled down to the People's Movement for the Liberation of Angola, or MPLA, against the National Union for the Total Independence of Angola, or UNITA.

The MPLA was the intellectual socialist party propped up by Cuba and the Soviet Union. UNITA was the rural right-wing peasant party backed by South Africa and the US. By the time fighting ended in 2002, half a million people had died, more than 4 million were displaced and, according to estimates on the high end, 1 million land mines were buried.

Angola has three major demining organizations: the Mine Advisory Group, the Norwegian People's Aid and Halo. They work closely with the Angolan government's national authority on demining.

As we near Cuito Cuanavale that first day, the sun is setting. At first glance, the town doesn't leave much of an impression. It consists of a short row of ramshackle shops and a few dirt roads. But this town is famous for the seven-month Battle of Cuito Cuanavale, considered a turning point in Angola's civil war and one of Africa's biggest battles in the last century. Although it ended in a stalemate in 1988, the battle eventually led to the withdrawal of both South African and Cuban troops from Angola.

The fight also had ripples outside of Angola. Nelson Mandela called Cuito Cuanavale "the turning point for the liberation of our continent — and of my people — from the scourge of apartheid."

The battle's other legacy, though, is tens of thousands of land mines left behind.

It's dark when we finally pull into our camp. Legg tells us to bring flashlights when we go to the latrine. Apparently, black mambas and spitting cobras like to cozy up there during cold nights. We ask if we'll encounter those poisonous snakes elsewhere. We might, he says.

"To be honest, don't be worried about the snakes," he adds. "Worry about the minefields."

From Google Earth to mine-sniffing rats

The relationship between mine clearance and tech is, at best, complicated.

Researchers are always trying to come up with new approaches, but for decades the standard method has been human beings on their hands and knees, meticulously waving metal detectors before them. The mine clearers set up narrow lanes for themselves, inching forward. The approach is called "one man, one lane," and that's how Angola has been demined for years — one lane at a time.

The Halo Trust, in Angola, uses Google Earth Pro to create detailed maps of minefields. James Martin/CNET

The idea is "slow and steady wins the race." But over the years, mine clearers have gotten smarter about how to find the minefields, even if the digging part is still pretty analog.

Their most powerful tech tool is Google Earth, a high-resolution digital model of the planet. You've probably used the software to gawk at satellite images of your house or zoom in on your car in the driveway.

Halo uses Google Earth Pro, a paid version that Google licenses for free to many charities, for virtual reconnaissance. Demining teams can look at aerial photos of an area and pick out patterns. If there's a village next to a field, but the field remains conspicuously uncultivated, you can probably bet it has mines there.

"There are local people in Angola who know where a cow blew up last week, or saw a group of soldiers there years ago," says Rebecca Moore, head of Google Earth. "Showing them the imagery and terrain is a very powerful tool for collaborating."

When demining organizations send people into the field to talk to locals, they record the area's GPS coordinates, then plot those GPS points into Google Earth to create what they think is the minefield's perimeter. They can then overlay that perimeter onto satellite images to create a detailed map.

Luan Jaupi, Halo's global IT officer, discovered Google Earth 10 years ago. Before that, the group used scanned digital copies of hand-drawn topographical maps created during Portugal's colonization. They were hopelessly outdated.

"Some of these places have the fastest growing populations in the world," says Google Earth's Moore. "So those old maps are almost worse than useless. You might gain a false confidence that you understand the situation on the ground."

When Google Earth lacks images that Halo needs, Jaupi just calls Google to ask for them. Then Google updates the software. "It's a little bit of a special secret for NGOs," says Moore. Google typically prioritizes updates for places where lots of people live. "But we know there are some very important places on the planet that are more remote."

Mine clearers also use drones for reconnaissance work. If they need an image quickly — say it's missing from Google Earth or clouds muddled the picture — they can fly a drone to take photos, says Jaupi. The images are usually clear because the drones fly below the clouds. But there are limitations: drones can't fly for long, and they cover only small areas.

Most deminers agree Google Earth is a powerful tool for surveying minefields. Everything else is experimental.

The long, empty road to Cuito Cuanavale. This town is in a region so remote it's known as "the land at the end of the world." James Martin/CNET

A Tanzanian organization called Apopo has trained giant rats to sniff out TNT in land mines. These are Gambian pouched rats, which are nearly blind but have a phenomenal sense of smell. The rats weigh too little to set off the mines, so they wear tiny harnesses and roam the minefields for the scent.

They're adorable. But there's the concern that animals may miss something. Organizations in France and Croatia have been testing to see if bees can sniff out land mines as well.

There's other proof of concept stuff, too. Scientists at MIT have engineered spinach plants to detect "nitroaromatic" compounds — chemicals found in land mines — in the groundwater. If the chemicals are present, an infrared camera will reveal fluorescent coloring on the spinach leaves.

Then there's the Mine Kafon, which detonates mines as it rolls over the ground. The wind-powered, giant steel ball looks like an enormous dandelion, with spokes sticking out from its center. It was designed by Massoud Hassani, a former refugee from land mine filled Afghanistan. Many regard it as more design concept than practical.

It's a whole different story for something to work every day with lives on the line, says Michael "Moe" Moore, from the Landmine and Cluster Munition Monitor, an organization that keeps statistics on mines across the globe.

"All these tests, they're all done in prepared fields," he says. "An actual minefield is, well, an actual minefield."

"Suddenly, I just saw dust"

The hallway of the Medical Rehabilitation Center at Bomba Alta, Huambo, has a dozen old prosthetics on display. Most are built with outdated technology, some of them homemade. Inside a physical therapy room a few feet away, Abel Mbussulo and Amandio Manuel sit on a white exercise staircase with wooden steps. Patients use those steps to learn how to walk again after they get their new legs.

Abel Mbussolo still waits for a prosthetic leg after his first one was destroyed in a house fire. In 2012, he stepped on a trip wire while walking to farm his crops. James Martin/CNET

Mbussulo is still waiting on a prosthetic for his left leg. He'll likely be waiting awhile. The clinic had to stop making new limbs because of a lack of materials and funding. The building itself is run-down, with peeling paint and broken windows.

Mbussulo, who grew up in Huambo, has glassy eyes and a five o'clock shadow. A farmer by trade, he cultivates crops like corn and beans. In 2012, while walking with his brother to the fields, Mbussulo stumbled on a trip wire, a thin piece of metal string hidden along the ground to detonate land mines.

"Suddenly, I just saw dust," he says, through a translator. His leg was blown off below the knee, and his brother ran to find help.

At one time, Mbussulo did have a prosthetic. But because there was shrapnel in his leg from the blast, he would sometimes take off his artificial limb to relieve the pain. Then two years ago, his house — a grass hut — caught fire. The house burned and, with it, his prosthetic leg. Now the shrapnel is out, but the wound still occasionally hurts. "When the moon goes to darkness, I feel some pain," he says.

Manuel, by contrast, has two prosthetics. He lost both legs after stepping on a land mine in 1986, when he was a logistics officer in the civil war. He doesn't want the same accident to happen to his wife and 12 kids. "Be patient. Be careful in your movement," he says he always tells them. "Don't touch objects you don't know."

Still, he's endlessly optimistic. He says he can do anything any other person can do. Even with two artificial legs, he drives every day. He asks us to snap a photo of him in his SUV, then drives away.

Their stories aren't uncommon. In Angola, everyone knows someone who's been killed or maimed by a land mine.

The Diana effect

In the San Antonio neighborhood of Huambo, a small, pink hotel overlooks a dirt road at a lively intersection. Townspeople walk with their dogs. Nearby, dozens of schoolchildren, in white robes that look like lab coats — the customary school uniform in Angola — run and laugh as class gets out.

"I always tell those hotel owners they should rename it the Hotel Diana," says Gerhard Zank.

He's the head of Angola operations for Halo. He's South African by birth, Scottish by upbringing. The bald, former military man is strongly built, with perfect posture. He looks exactly like you'd expect a Gerhard Zank to look.

He doesn't think the hotel owners are aware of the history of this particular strip of land. So when he suggests the new name, "They think I'm joking, but I'm serious."

In January 1997, Princess Diana brought attention to Angola's land mines by visiting a minefield in Huambo. John Stillwell / AFP/Getty Images

He's talking about Diana, Princess of Wales. When she walked in this exact spot 20 years ago, it looked nothing like this. The photos are now iconic: Diana, wearing a clear, plastic visor over her blonde cropped hair. She's got a blue body armor vest on, with a Red Cross emblem pinned to the top. She's walking along a path lined with those same foreboding skull and crossbones signs, next to wild, untamed grass.

The event drew global news coverage, and the images are a lasting part of her legacy. Paul Heslop, now the chief of programs at the United Nations Mine Action Service, was responsible for leading her through the minefield 20 years ago. He remembers his exact thoughts the moment he realized what he'd be doing.

"The polite version is, 'Oh, we'd better get this right.' The impolite version is, 'Fuck, we better not fuck this up,'" he recalls. "I really didn't want to be on the front page of newspapers the next day saying this was the man that had Princess Diana blown up."

Diana was embarking on a campaign to advocate the banning of land mines. When she arrived in Angola, she first toured Cuito Cuanavale. There, she met with amputees at a hospital and then continued onto Huambo to walk through the minefield.

"There couldn't be a more appropriate place to begin this campaign than Angola," the princess said, "because this nation has the highest number of amputees per population than anywhere in the world."

The same area where Princess Diana walked 20 years ago is now a busy intersection where school kids play. James Martin/CNET

A few months after her death in August 1997, Britain signed the Ottawa Treaty banning land mines. Two decades later, 162 nations have signed the treaty, but 34 haven't. The most notable exceptions: the United States, Russia and China.

As the sun sets in Huambo, Zank uses Google Earth photos to show the before-and-after of where we're standing. Where Diana once walked amid tall grass, there's now the hotel, school and rows of houses.

"If you were to retrace my mother's footsteps through Huambo in Angola today, you would see no danger signs and have no need for a helmet or body armor," Prince Harry said in April, during a speech at Kensington Palace to commemorate the anniversary of his mom's visit. Within the next year, Huambo will likely be the first province in Angola to be declared completely mine-free.

But the prince warns it's still too soon to celebrate. "In marking how far we have come, we must also acknowledge that there is much more which needs to be done to fulfill the commitments of the Ottawa Treaty," he said.

He knows the situation firsthand. In 2013, he traveled to Cuito Cuanavale to see the minefields, sleeping in a tent at Halo's compound. Zank and Antonio showed him around. At the NGO's headquarters, there's a framed picture of Antonio and the prince exploring the terrain. Harry's biggest complaint is the nations who planted the mines, like Cuba, aren't doing more to clean them up.

Money for demining comes mostly from abroad. The US State Department is the biggest contributor. Sixty percent of Halo's funding, for instance, comes from the US.

Prince Harry"Funding demining programs is the most direct contribution we can make to assist Angola's rural communities and to contribute to the diversification of the economy," Helen La Lime, US Ambassador to Angola, says in an email, "because the land cleared is immediately put back into use for agriculture, homes and schools."

But the funds are dwindling. It would take an estimated $275 million to finish off demining in Angola. Current funding is less than 20 percent of that.

With at least 40 percent of Cuito Cuanavale still uncleared, including an 18-mile-long minefield, and other large swaths of Angola untouched, the goal of Landmine Free 2025 seems nearly insurmountable.

"With resources it will be possible, but as it is now it will not be possible," Antonio says. He stops, thinks for a moment and rephrases. "It's very tough, even if we have resources."

"They've all got families"

Halo's training facility for deminers is located a few miles outside Huambo. It's in a large field filled with golden, head-high grass. There's no shelter or shade. Next to the field is a camp where the trainees live. It's designed to mimic a real minefield experience. So the trainees sleep in shared canvas tents and eat in a communal jango, a traditional round-shaped hut with a thatched roof.

Becoming a deminer isn't easy. First, there's recruitment, which involves a full medical check to make sure potential deminers are physically fit for the job. Then, written math and comprehension tests and an interview. Next comes a monthlong training aimed to winnow out the weak. That's because it's a laborious job that demands extreme attention to detail.

Demining is a slow and potentially dangerous process, but The Halo Trust teaches trainees that proper protocols will keep them safe. James Martin/CNET

The current group of trainees is all women. They are part of a new initiative by Halo called "100 Women in Demining." The aim is to diversify Halo's ranks, boost mine clearance in the country, teach job skills to more women and attract donors. The goal is to eventually have 100 women working as deminers, medics, drivers and mechanics in Angola. This first class of 20 started training on June 5.

"They've all got families, they've all got kids, they've all got people to support back at home," says Legg.

During their first week, the trainees learn the rules of the minefield, the gear to wear and the types of mines found in Angola. The next weeks are spent in the mock minefield digging up bits of shrapnel and fuse-free mines. They work full days, wearing complete armor in the hot sun.

We visit the training facility during the last week of this phase of training. We, too, must wear full armor, even though the area is mine-free.

Legg walks the field, observing how each trainee is doing. We watch as one deminer homes in on something underground. Using her trowel, she gently excavates the dense, red dirt. Legg tells her not to make her trench wider than 15 centimeters. That's outside the safety zone.

"You get the foundation correct and everything else follows," Legg says. If not, "one little bit slips and another little bit slips and then someone does something stupid."

The next day all these trainees will be tested on their skills. It'll be a big moment. Those who pass go onto the next phase of training and begin work in a real minefield. Those who don't, go home.

The last day of demining in Cuito Cuanavale is uneventful. That's a good thing, since there are no accidents, no surprises.

At the minefield across the river, with the jumping land mines, the men pack up their gear for the last time. They roll their tool kits into their bags, pick up their rakes and metal detectors, and trek back to safe ground. No one speaks. They leave the area, walking slowly in a row.

As they pass, they give a farewell nod to Antonio and Legg.

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The men worked here for 20 days. They cleared 103,980 square feet of land, destroying 65 mines. They were nearly done — only two more blocks remain to be swept.

Off to the edge of the minefield, Manuel Bimba, a local resident, has a small farm. For the dry months of the year, he lives here with his 16 family members growing corn and cassava. Like most Angolans, he's all too familiar with land mines — one killed his aunt in 1992. He says he tells his kids not to go anywhere near that deadly patch of land.

Back in Huambo, all of the women trainees passed their tests. After we left Angola, they started working in live minefields for their next stage of training. And as it turns out, Halo placed them in Cuito Cuanavale.

Much of what the men couldn't finish in the two minefields we visited, the women did.

So even though demining operations in Cuito Cuanavale are stopping and tens of thousands of mines there remain unearthed, there's some small consolation. Soon, those two minefields will be fully cleared and turned over to Bimba and the other families who live nearby. And finally, after 30 years, these tracts of land can go back to the people living in the land at the end of the world.

Photography by CNET Senior Photographer James Martin.