The perilous journey across Mexico for migrants trying to reach the US - this is where it starts

As the sun rises over the Usumacinta River between Guatemala and Mexico, the silence is broken by the sounds of people awaking after another night camping on the riverbanks.

Migrants bathe in the river

Soon the ferrymen who pilot a flotilla of makeshift rafts constructed of planks strapped to very large inner tyre tubes, begin their never-ending trade of moving fruit and vegetables, construction equipment, crates of beer and liquor, motorcycles and bicycles, but above all - people.

This is where thousands of migrants heading to the United States begin what they hope to be the last leg of their often epic journeys to the northern border with the US.

A migrant sleeps near the river

1600 miles through Mexico is all that separates them from their dreams of a new life.

I've been here many times to report over many years and I am never less than amazed at the number of people who attempt this journey, and the sheer number of small children.

Migrant caravan leader Davyde is seen in the white vest

But this time I've noticed some things have changed.

Whereas a few years ago the migrants were almost entirely from Southern and Central America, now they're from all over the world.

On this trip we have met young men and women from China, Egypt, Jordan, Somalia, Mauritania, Kazakhstan, Haiti, and Gambia, to name a few.

Another major change seems to be the attitude of the Mexican authorities.

In the past, the passage of the migrants north, while not easy, wasn't noticeably hindered by the Mexicans.

Now though, with the issue of migration on its southern border a political hot potato in a United States election year, the Mexican authorities have got the message from the United States that thousands of migrants on the border fence is not a good look.

A man sleeps with his daughter near the river

What we have witnessed is a system that doesn't actually stop the migrants moving north, but makes it bureaucratic, confusing and often contradictory enough that the migrants don't know what to do.

A woman and baby wait near the checkpoint

The US has a problem with the numbers, so people travelling through Mexico are shifted from one location to another and left, and then shifted again - never really making any progress.

Legally, migrants and asylum seekers cannot be stopped, but they can be asked to follow rules (or have their paperwork torn up), and if the rules keep changing, there is nothing they can do about.

After crossing the Usumacinta River from Guatemala, the migrants rest in the city of Hidalgo, before forming into groups known as "caravans" to begin their journey north.

They travel together for safety from gangs and criminals who prey on the migrants.

We joined a pop-up caravan shortly before dawn; they move at that time to take advantage of the cooler temperatures.

Mexico's National Guard patrols the area near the river

This caravan is led by a young Brazilian man named Davyde who is with his wife and sister-in-law.

Migrants gathered at the park in Tapachula

"Brazil is not good, I can't make enough money to pay the rent, America would be great," he told me when I wondered why he'd made the journey from Brazil.

As we walk with the group of 200 plus people, the sun rises and the temperature soars.

Whole families, very young and old, travel along the sides of busy motorways, heading north - always north.

Walking with the group, we meet Mayra Ferrerr from Acarigua in Venezuela.

The 40-year-old is travelling with her two sons and some fellow Venezuelans.

They've all become friends along the way. Mayra has breast cancer, and she's trying to get to her family in the US.

She's prepared to risk everything.

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"We left Venezuela because there is no education, because there is no medicine, because I am an oncology patient and I cannot get treatment in the public health system for breast cancer," she told me.

"And well, I needed to go somewhere where I can be checked and continue treatment."

Mayra explained that she's doing chemotherapy in the form of pills, but that she stopped taking them so that she wasn't too weak on this journey.

A Mexican military vehicle near the checkpoint

She says it's tough, but that she and her family and friends plan to keep going.

"Well, it is hard because unfortunately in many towns we have crossed, they take advantage of our situation, our need to keep moving forward, and the costs, be it water or bread, they make it more expensive for us."

Most of the migrants are carrying tents, an absolute necessity for crossing the Darien Gap - a notorious jungle crossing on the migrant route, which lies between Colombia and Panama.

Said is seen holding his son

Mayra says the tents are worth holding on to.

"We have kept our tents because we have nowhere to stay, and we have to set up the tent and camp anywhere, so that we can keep moving forward."

Migrants from China, Kazakhstan and Nigeria

After a few hours of walking the migrants approach an immigration checkpoint where they are met by Mexican immigration officers.

We keep filming as they are told they will be taken north to the first major city in southern Mexico called Tapachula.

The immigration officials give the migrants water and assure them that they are allowed to continue their journey north, that the involvement of immigration is simply to offer them a ride to Tapachula and a free meal.

The migrants are sceptical, but over and over they are assured that once they are in Tapachula they can get paperwork done and continue.

The ones who agree have their identity cards and passports logged and checked, and then they're loaded onto minibuses.

Mayra, her two sons, and her friends all agree to go in the migration minibus to Tapachula.

This doesn't mean however that a journey further north is going to happen anytime soon.

At another immigration checkpoint on the outskirts of Tapachula, crowds surge around immigration staff, waving their papers.

Mayra and her son wait to board a minibus

All they're trying to do is get on a bus north, but the Mexican authorities assumed assistance has dried up.

Christian Heredia with his daughter

America does not want them in the north and nor it seems does Mexico, so they're in a limbo.

At multiple checkpoints we saw what is developing into a multinational mess.

Groups of young Chinese men and women take shade amongst Jordanians, Egyptians, Somalis, Gambians, even two friends from Kazakhstan.

The list of nationalities is remarkable, not least because of the distances they've travelled.

Said is a 28-year-old Afghan who worked for a British NGO until the Taliban arrived in Kabul in August 2021.

He says he got his paperwork to leave from Kabul Airport at the time, but abandoned his plans after a suicide bomb went off at the evacuation point.

Said's father and two uncles were killed by the Taliban, and he sees no safe future for his family there.

Indeed, he asked us not to show his face or use his full name because it would be dangerous for family members still in Afghanistan.

Said is travelling with his wife, three young children, and his 74-year-old grandfather who has stage one Alzheimer's.

Said told me that other migrants have nicknamed his grandad the "warrior" for undertaking such an intense physical journey in his older years.

The family has been on the move for two years.

"I realised I am on my own, I have to do it for myself, for my family, I've realised nobody is going to help me," he told me.

Said knows the political mood in the United States ahead of the presidential elections in November will be a factor in their chances of making it.

"I believe in God, I know I am in Mexico and 90% of the people are arriving there, actually, before the election, I need to get there before the election because I don't know the next president, what he will do and what he is thinking about refugees like us," he said.

Amongst the migrants we also come across 14-year-old Edgar Fonseca Cepeda.

He is completely on his own; an unaccompanied minor migrant.

Edgar travelled from Venezuela to Colombia where his grandmother, who had been caring for him, died.

Now he is trying to get to his mother who is in Washington DC and has undertaken this journey on his own.

We arrange for him to speak to his mother Carolina on a video call.

It was heartbreaking to witness.

Both mum and son started crying, and his mum kept saying how sorry she was that he was having to do this journey alone.

The day before, Edgar had explained to her that he, along with another group of migrants, had been kidnapped by a gang - he was only released after handing over 75 US dollars scrambled together by fellow travellers.

"We decided to come here on foot, which is a risk, and well, before Tapachula, just before we got here, we had already walked about six kilometres, we were stopped by a few bikers," he explained to me.

"That's when they told us not to cry, not to scream because nothing was going to happen to us, we thought that we were going to be surrounded by immigration, but no, they took us to a chicken coop…"

The group, including Edgar, say they were held for 8 to 10 hours.

We've heard exactly the same testimony from a number of migrants we've spoken to in the last few days.

"The truth is, it was horrible that chicken coop, people holding guns, I'm not used to seeing things like that, it was really scary," Edgar added.

We spoke to his mum Carolina, and she asked us to take him to the authorities, saying it was too dangerous for him to continue alone.

Edgar says he hasn't seen his mother for six or seven months.

"It's really very, very hard, I miss her so much, that's why I've done all of this."

Edgar bade an emotional goodbye to his new travelling family, the strangers who helped look after him on the journey.

He is safe now but when he will see his mother again nobody can say.

All these migrants are in a sort of vortex - not being stopped from travelling north but not being allowed to either.

The day after meeting Mayra and her group of family and friends heading north, we travelled again south to the river.

On our way back we recognised some of Mayra's group on the side of the road, exactly where they originally started.

We were confused, so we pulled over to talk to them.

They explained they were taken north to Tapachula, given some food, waited about an hour not knowing what was happening, then put back on the minibus and sent straight back to the riverside where they started.

They told us they were given additional paperwork, and then, as they put it "thrown out on the street".

I asked one of them, Christian Heredia, if the authorities acknowledged that taking them all the way back doesn't help.

"They're delaying us, yes, they know, of course, but as I was saying, they are the law here, here we are nobody, so they do as they please with the migrants. Right? That's the truth," he replied.

Christian says many of the migrants we had seen loaded into the minibuses and promised a ride to Tapachula the previous day had been pushed back to the river just like them.

They suspect the authorities only promised to look after them because of our presence, otherwise they believe the migration officials probably would've just driven them straight back down to the river.

Local buses don't usually pick up migrants because they're not allowed to, but standing on the side of the road with fresh papers, Christian and the group were able to flag down a minibus to take them back to Tapachula.

They reunited with Mayra and her boys in the main square where migrants from all over the world gather.

They, like everyone there, refuse to accept defeat. But their mammoth journeys are far from over.

Indeed, their difficulties continue.

The last we heard from Mayra and her friends they'd been robbed at gunpoint in a bus taking them further north.