An annual pilgrimage in which the relatives of the missing follow the steps of their loved ones through Mexico.

Veracruz, Mexico – The bus is quiet, the only sound is the hum of the engine and the murmur of a couple of women talking near the back. The rest are fast asleep, resting against the windows or each other.

They are older men and woman, dressed modestly, clutching canvas bags and rucksacks on their laps. Farmers, market stall owners, bakers, housewives. Working class people, many of whom have never before left their own countries in Central America.

Desperation has pushed them to embark on an exhausting journey to some of the poorest and most dangerous parts of Mexico.

The reason is tied with chord around their necks. A laminated plastic placard, each one with a large photo, a name and date. All of the 42 people in the caravan put theirs on the moment they start the day.

The photos are of their relatives – sons, daughters, brothers, sisters. The date is when each one went missing in Mexico.

Lilian, left, last heard from her sister just before crossing the Arizona desert, in Altar, Sonora. Noemi, right, is looking for her teenage son, he was 15 year of age when he disappeared, he was crossing the desert with her cousin and they all run away when they heard people talking on their radios, he hasn’t been seen since [Encarni Pindado/Al Jazeera]

The caravan

This is the caravan of mothers, whose children have disappeared on the migrant routes going from Central America, through Mexico to the United States.

The rights organisation Mesoamerican Migrant Movement has been organising this caravan for the past 12 years. It’s an annual pilgrimage of desperation in which the relatives of the missing follow the steps of their loved ones through Mexico, hoping to find them.

Guatemalans, Hondurans and Salvadorans in particular have been heading to the US and Mexico for years, trying to escape the poverty and violent gangs of their homelands. But in this country more danger awaits them. They are a valuable commodity for powerful cartels who kidnap them, squeeze their families for ransom money, then often either kill them or enslave them in prostitution or drug trafficking.

Tens of thousands of people are estimated to have disappeared.

Jaqueline Morales is one of them. Her young, beautiful face stares out of the photo hanging around the neck of her sister Lilian, who has been looking for her for nine years, while raising Jaqueline’s children by herself.

Lilian is a quiet, middle-aged woman, far from home, clinging to a fragile hope.This is her third time on the caravan. “I have faith in God and I know that my sister isn’t dead and that at some point I’ll find her,” she says in a practical tone.

And then she begins to cry. “The hole that they leave in our hearts no one can fill. It’s really hard to lose a loved one and any chance I have to look for her, it doesn’t matter where, I’ll go.”

The same mixture of bewilderment, sorrow and determination is ever present among the 42 people in the caravan.

Every day they travel to a different town.

This time it’s Cordoba, in the gang-ridden state of Veracruz. They spread the photos of their missing relatives on the ground to make sure they’re seen, then each says the name of their relative through a megaphone.

Holding banners they march around the centre, joined by local people who have also lost family members at the hands of organised crime or, they say, Mexican authorities. As they march, Lilian and others give out flyers to try and spread the message.

WATCH: Mexico’s Disappeared

Looking for a miracle

It’s an all-consuming, two-and-a-half week journey in which they’ve also combed dive bars, cemeteries, migrant shelters and prisons. They look everywhere for a clue or someone who knows something that could lead to a miracle – finding a loved one.

The caravan organisers say that they’ve managed to find some 270 people in the 12 years but that’s still a drop in the ocean: they estimate that there are around 70,000 missing migrants in the country.

To make any inroads in finding out what has happened to them, they would need help from Mexican authorities.

But that simply isn’t forthcoming, says Martha Sanchez Solis, one of the caravan organisers.

According to her, officials stonewall relatives looking for answers because they don’t want their own wrongs to come to light.

“It’s not convenient for the transit country [Mexico] to make known the crimes that are committed here, especially because there’s lots of authorities that are colluding in them. The lesser sin is omission – when they just do nothing – but many times it goes further than that and there’s direct participation from Mexican authorities.”

Other migrant rights organisations and shelters across the country share Martha Sanchez Solis’s assessment – that officials are at best often negligent, at worst involved.

WATCH: Separated – Deported mothers and their American children

Norma Yanet Rodriguez fainted just before meeting her sister, Amalia Aida. Amalia had disappeared 37 years before. Aida had tried to contact her family but they had moved her letters were returned [Encarni Pindado/Al Jazeera]

Angela Arranda, 63, a grandmother travelling from her native Honduras for the first time, felt this first hand.

From her seat at the front of the bus she explained to Al Jazeera that her daughter Hilda Alvarado had been in a Mexican jail for a whole year – on drug-dealing charges that she says are trumped up – before migrant rights groups could put enough pressure on authorities to allow her to contact her family and tell them she was alive.

“When I heard her, I started to cry all over the place. I couldn’t believe it was her,” Arranda told. Hilda has been in jail for four years now. Angela is taking care of Alvarado’s children alone.

READ MORE: On Ayotzinapa anniversary, all eyes on Mexico

Easy prey for criminal gangs

Al Jazeera’s interview requests to Mexican authorities went unanswered, but they have given serious thought to the migrant issue.

Their solution has been to stop them from crossing the country altogether. The Mexican government has poured millions of dollars into Plan Frontera Sur, which started in 2014 and features a web of checkpoints and patrols to catch those who cross the country’s southern border.

Migrants rights groups say that has forced migrants to travel through more isolated areas to avoid detection, where they are even easier prey for criminal gangs.

But they still keep coming. With Donald Trump about to take the US presidency, Central American governments say more people than ever are making the journey. With so many dangers on the route, it’s a measure of how desperate the situation is in El Salvador, Honduras and Guatemala – countries suffering from violent gangs and widespread poverty – that the stream continues.

READ MORE: Guatemala – The indigenous population too poor to stay

Omar has been frantically searching for his son, David, who disappeared right before reaching the US border [Encarni Pindado/Al Jazeera]

Omar Jarquain’s son David was one of the many who saw little choice but to head to the US, after being beaten up and repeatedly threatened by gangsters in El Salvador.

Riding on the bus as it trundles through the Veracruz countryside, Omar told Al Jazeera he tried to dissuade David. When he couldn’t, he sold his car and remortgaged his house to raise the $8,000 for a people smuggler to guide his son safely to the States. It left him in debt but he hoped David could pay him some of the money back when he arrived.

But David disappeared in Reynosa, Tamaulipas, one of Mexico’s most notoriously violent cities. Omar remembers their last phone call.

“He was content, telling me he was already there [at the border]. I was really pleased and asked him how many days to cross over. He said, in five days and then I’ll call you. Those five days have turned into two years and five months. I don’t know where he is or even if he’s dead,” Jarquain told.

Jarquain has been frantically searching for him since, at the same time struggling with the debt. He has lost his house. In the midst of the nightmare he’s found consolation with an association of parents in the same position in El Salvador.

“We’ve become like a family,” he says.

La Ceiba, organised a Mayan ceremony for the parents of the missing migrants. In this pre-Columbian ceremony, fire, candles, flowers, sugar, copal and other elements are used for the purification of participants and to pay respect to their ancestors and the earth. [Encarni Pindado/Al Jazeera]

Finding each other again

It’s that solidarity that keeps those on the caravan going through the long, frequently fruitless days.

They start each morning by holding hands and praying together. In the nights they hold mass in sympathetic churches along the way. They sleep often in the migrant shelters dotted along the route. But their list of allies is small, and the power and resources they have is limited.

At the end of the two and a half weeks, three members of of the caravan had found a relative. One of them was Norma Santizo, whose sister Amalia had left Guatemala decades before, trying to start a new life in Mexico after losing a child.

They had last seen each other 37 years before.

On a warm Veracruz night, Norma and the rest of the caravan waited to see her in a migrant canteen set up by local volunteers. As the hours ticked by and Amalia didn’t come, it all became too much for the niece travelling with Norma – who suddenly fainted.

Finally she arrived. Tears pent up over decades came spilling out as the two embraced.

The other parents stood around chanting: “It can be done, it can be done”.

It was a brief moment of catharsis and triumph for the caravan organisers and other relatives. The next day they would go back to the long, painful task of looking for their own relatives.

Photogallery

The XII caravan of mothers of missing migrants coordinated by the Mesoamerican Migrant Movement, arrives in Frontera Comalapa in Chiapas, south of Mexico on November 15, 2016. [Encarni Pindado/Al Jazeera]

The caravan arrives at La Mesilla, where the group is given a temporary visa, to tour Mexico looking for their missing relatives. [Encarni Pindado/Al Jazeera]

The first place the caravan visits is Frontera Comalapa, famous for its network of sex traffickers who abduct young migrants tricking them into the sex industry [Encarni Pindado/Al Jazeera]

The caravan arrives at La Ceiba, a popular educational centre in the south of Chiapas, which works with indigenous communities. [Encarni Pindado/Al Jazeera]

Most caravan participants are religious. For them it is important to find a moment of peace, as the caravan can be an emotional rollercoaster. [Encarni Pindado/Al Jazeera]

The same mixture of bewilderment, sorrow and determination is ever present among the 42 people in the caravan [Encarni Pindado/Al Jazeera]

Anita Celaya is the head of Cofamide, the Committee for disappeared migrants of El Salvador. Like many mothers, she joined the organisation when her son went missing in Mexico years ago [Encarni Pindado/Al Jazeera]

Lilian Morales, from El Salvador, travels to Sonora desert, searching for clues about the disappearance of her sister. They last she spoke just before her crossing of the Sasabe/Arizona desert Sonora. While in Nogales, Colibri, a forensic organisation, working to identify 900 bodies found in the desert, collected DNA from Lilian to search in their database [Encarni Pindado/Al Jazeera]

Mothers from the caravan put the images of disappeared migrants against the separation wall in Nogales Mexico. The militarisation of the border, forces migrants to walk much further into the desert, in order to avoid immigration officials, and risk their lives trying to cross irregularly into the US [Encarni Pindado/Al Jazeera]

Amalia Aida Rodriguez hugs her sister and niece during her reunion after 37 years without news of each other. Amalia disappeared in Mexico when she was 22. She married and had children in Mexico, but she had no legal status, so she could not go back to Guatemala. Eventually her daughter got in contact with the Mesoamerican Migrant Movement who helped her find her family [Encarni Pindado/Al Jazeera]

Production: Mireya Lopez. Camera: Gustavo Huerta