About 1.9 million Venezuelans have fled their collapsing nation since 2015 in one of the largest migrations in the world in recent years. The most desperate cannot afford a bus or plane ticket, and so they risk their lives to escape on foot.

Every day, more than 650 migrants start on the walk out of Venezuela. They rush illegally across the border with Colombia, frequently encountering armed criminals. They walk for miles along roads, carrying their belongings. They wrap themselves in blankets, bracing against the cold of frigid mountains.

For nine days, a team of Associated Press journalists followed a Venezuelan mother and daughter as they crossed three borders and nearly 2,700 miles (3,460 kilometers) — about the distance from Los Angeles to New York City.

This is an account of the people, places and dangers migrants encounter along the way.

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A PERILOUS CROSSING

VILLA DEL ROSARIO, Colombia — Most Venezuelans buy a bus ticket to the border with Colombia but cannot cross through an official checkpoint because they lack the proper documents, such as a passport.

Instead they traverse one of hundreds of illegal dirt road crossings that are ruled by armed criminals dressed in green fatigues. These illegal groups frequently rob and assault migrants who can't pay the equivalent of $10 in Colombian pesos or Venezuelan bolivars, or about half what a Venezuelan earning the minimum wage might make in a month.

Aurelix Lira, 20, and her boyfriend were robbed of their cellphone after being unable to hand over any cash.

"You'll have to pay!" said an armed man who rummaged through their belongings.

Authorities have struggled to wrestle control of the no-man's land between both nations. In the meantime, Venezuelans are being recruited into illegal activities such as drug trafficking.

"They are very much in the wind," said Jeremy McDermott, executive director of InSight Crime, a group that studies organized crime in Latin America, "which makes them extremely vulnerable to exploitation and recruitment by organized crime."

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THE WAILING WALL

LOS PATIOS, Colombia — The small stand where Martha Elena Alarcon, 54, sells soda, chips and sugarcane juice is where many migrants fleeing by foot stop for a moment's rest. When Venezuelans began arriving at her doorstep about a year ago, she'd give them water and bread.

As the numbers skyrocketed, she asked them to write a message.

The walls of the tin roof building are now covered in hundreds of messages written on nearly worthless Venezuelan bolivars and bright colored sheets of paper.

Five travelers writing in black ink said they were "walking to a better life thanks to our president, who is either blind or a brute and making everyone in Venezuela flee." One pregnant woman traveling with her 3-year-old old daughter, Sofia, said the journey had been trying and wrote, "God please protect us."

The list of names in each note is one of the only written records documenting who is walking and where. Alarcon recalled how one woman came across the name of a cousin she had not heard from in one of the messages.

"She's OK!" the migrant told her in relief.

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A FRIGID PARAMO

TONA, Colombia — The road leading to the city of Bucaramanga passes through a frigid paramo known as "the icebox" that has struck fear into the hearts of migrants unprepared for temperatures down to 10 degrees below freezing.

Marta Duque, 55, welcomes upward of 300 migrants a day into her home in Pamplona, where she gives them food and warm clothes and warns against sleeping outside.

"They are risking their lives and those of their children," she said.

Carlos Valdes, the head of Colombia's forensic medicine office, said he believes walkers have died from the cold but was unable to provide a number. One migrant told the AP he saw a family burying someone on the side of the road. Others have described seeing crosses and stones bearing names and death dates.

Jonathan Suarez, 23, sat with tears streaming down his cheeks as he tried to get a ride. The previous day he had walked 25 hours and slept on the side of the roadway. The thought of his two girls back home - ages 3 and 8 months - kept him going.

"I must press on, for them," he said.

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PARQUE DEL AGUA

BUCARAMANGA, Colombia — Public parks across Colombia have turned into makeshift shelters for migrants with nowhere else to go.

On any given day, about 400 Venezuelans convene in the Parque del Agua in Bucaramanga, many fresh from long walks and eager to rest. Pastors deliver sermons and hand out Bibles. Charity groups come with hot meals in Styrofoam containers. And Venezuelans who are complete strangers sleep side by side on top of flattened cardboard boxes.

In some parts of the country, authorities have forcibly removed migrants who convene in public spaces. But many Venezuelans say they are unable to afford even the simplest lodging.

Geraldine Aguilera, 22, a former architecture student, arrived at the park after walking and hitching rides from the border with her sister.

"It's hard sleeping next to people you don't know," she said. "You don't know if they're going to hurt you. But necessity forces you."

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ISLANDS OF REFUGE

PEROLES, Colombia — Migrants traverse through extreme temperature changes as they travel through frigid mountaintops and scorching, flat valleys.

As they walk through remote country roads, freighter trucks barrel by, coming within a few feet of Venezuelans trekking along the narrow shoulder.

Much of the journey through Colombia takes them through isolated farmland where gas stations have turned into small islands of refuge for hot, exhausted migrants.

Gas station attendant Manuel Velasquez has seen the migration crisis up close from where he fills up trucks in rural Peroles. Many of the migrants he sees come with their feet blistered and knees swollen, on the verge of collapse from hunger and dehydration. The woman who stands out to him the most was being pushed in a wheelchair to Ecuador for cancer treatment.

"I'm terrified by what is happening," he said.

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GETTING A RIDE

LA DORADA, Colombia — When they get lucky, migrants hitch rides or collect enough money to buy bus tickets to reach their next destination.

One of the first rides for migrant Sandra Cadiz and her daughter came on the back of a caravan-style truck, where they clung to the side wooden panels every time the vehicle braked and swerved.

On another long, hot day, a Venezuelan man took them on the back of his motorcycle to a gas station. And about halfway through Colombia, generous bikers, drivers and others who spotted Cadiz and her daughter on the side of the road had given them enough money to purchase bus tickets.

But the vast majority of trucks and cars don't stop for the Venezuelans they see walking. Many have heard stories about migrants committing crimes. Truckers say they'd be fired if bosses found out they were carrying migrants and that their every move is tracked by GPS devices. Others fear incurring heavy fines from police.

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DESPERATE MESSAGES

CALI, Colombia — A cellphone is a luxury most poor migrant walkers don't have, so those interviewed by the AP often asked to use their phones to send messages to relatives.

One woman cried into a reporter's cellphone as she sent a message to her mother and toddler son back in Caracas after two days of walking.

"All of this is for you both, mami," she sobbed. "I love you so much."

Another young man arriving by bus in Cali sold his phone to get money for the journey. He used an AP phone to contact the only person he knew in the crime-ridden city — his friend's sister.

"It's Jesus," he wrote her.

"Jesus who?" she responded.

She eventually recognized his name and gave him her address. In a few subsequent messages with his friend, he said his stomach was in knots.

"I've gone about two days without eating," he said.

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HOPING TO CROSS

RUMICHACA INTERNATIONAL BRIDGE. Colombia/Ecuador border — The bus ride from Cali to Ipiales was full of Venezuelan families with young children crossing into Ecuador.

When they reached the Rumichaca International Bridge, the migrants filed into long lines and stood at least four hours in the cold. Some wore socks for mittens and used bath towels as blankets.

Many women with kids were turned back because they did not have written authorization from their children's father.

Those who did make it across found refugee-style Red Cross tents on the other side. Women and children were quickly escorted onto buses paid for by the Ecuadorean government that would take them all the way to the border with Peru.

Many men would have to wait several days longer.

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A LONG WAIT

AGUAS VERDES, Peru — At the crowded Peru-Ecuador border, many young migrants who had walked for weeks complained they'd been waiting days for authorities to process their entry request — and in the meantime weren't given any food or water.

As 21-year-old Jean Paul Flores spoke of his shared frustration to the AP, dozens cheered and applauded in agreement. Flores worked at an international call center in Venezuela and left behind his five-months-pregnant wife. He knew if he stayed, he wouldn't be able to buy diapers for his baby.

"Staying and accompanying her during nine months of pregnancy would mean sacrificing the childhood of my baby," he said. "It's not worth it."

He urged Peruvian officials to let them through swiftly.

"We just want to obtain our objective: To save our families from what is happening there," he said.

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SEARCHING FOR A NEW HOME

LIMA, Peru — The capital city of Peru — some 2,700 miles from where migrants start out on foot — is the final destination for growing numbers of migrants.

Over 400,000 Venezuelans now live in the Andean nation, most arriving over the last year. Many are drawn by Peru's economy, which is expected to grow nearly 4 percent this year, faster than other countries in the region.

While some migrants hope they'll return to Venezuela, most interviewed by the AP believed their move would be permanent. Their only hope was to earn enough money so they could bring the rest of their family, too.

Migrant Sandra Cadiz and her daughter initially stayed with her older son and his family, but the landlord of the tiny room didn't want so many people living there. In the week since they've lived in two different shelters.

"I have a home in Venezuela," Cadiz says. "But I don't have one here."