We arrive at Las Tecas camp on motorbikes, I can see it in the distance cut from the jungle, an open area surrounded by a series of wooden frames, covered by huge sheets of tarpaulin.
Beneath, there are over a hundred backpack-style colourful pop-up tents and dozens of hammocks strung from the wooden posts.
As we approach, we see hundreds of people milling around chatting, playing dominoes, or sat outside what I can only describe as a jungle internet cafe.
This is northern Colombia. We are in the middle of nowhere and there is electricity provided by a noisy generator on the side of the hill, makeshift shops, cafes, running water and clean toilets and showers – although they charge a dollar a pop for almost everything, and some here can’t afford that.
Las Tecas is an organised shanty town with a few extras.
I’ve been to more refugee camps, transit camps and migration centres than I can count, but this level of organisation took me by surprise.
The reason is money. The camp is operated by a large smuggling network, and their clients are migrants heading north to the United States.
In front of them lies a thick jungle infested with poisonous snakes, spiders, insects, criminal gangs, terrorist groups, and a 65-mile trek through rivers and mountains.
It is the Darien Gap – the gateway to Panama from Colombia, and the gateway to the United States of America.
For the migrants their last night in this camp is their last night of safety for a while.
If Everest has base camp, the gap has Las Tecas.
We strung our hammocks before night fall and wandered among the migrants, explaining we were joining them for part of their journey.
They’re from all over the world – Nepalese, Africans, Asians, Haitians, but mainly South Americans.
They were friendly and seemed both excited and nervous. What struck all of us was the sheer number of families, and the quite extraordinary number of small children.
I’ve read about the Darien Gap for years, and the only sensible conclusion anyone would reach, is that it’s too dangerous to cross as an adult, let alone as a child.
But the stream of migrants attempting this crossing is equally remarkable.
In the first nine months of this year 150,000 people did it. More than 20,000 of them were children. A decade ago, only barely 200 migrants attempted it.
The smugglers facilitate these daily moves and are making a fortune.
The migrants are desperate, and one can only imagine how awful their lives at home must be to take on this nightmare that takes at least five days in blistering heat and overwhelming humidity.
I’ll be honest, I was somewhat fearful, and I was only attempting a small chunk of the trip.
By 4 o’clock the next morning the camp is awake, breaking down tents and packing whatever they can carry.
Mums and dads get their children ready, dressing them, feeding them breakfast, filling their tiny backpacks, and slipping on their colourful wellington boots.
One baby had been bitten by insects during the night. She was covered in bites and her mother was scratching her back to try to ease the itch.
They haven’t even got to the jungle yet.
At first light they gather to take instructions from a man talking on a loudspeaker.
Then a gate opens, and they flood through.
One of their first obstacles of many is a river, and within minutes of setting off everyone is wet.
Slipping on rocks beneath the water little ones grab their parents, parents grab their children, hoisting them on to their backs and shoulders to try to keep them dry.
But everyone keeps moving.
We criss-cross the rivers following the migrants as they make their way along the valley floor towards higher ground. It takes them at least a day.
Against my usual judgement, we, like many here, are told by our guides to wear wellington boots.
The reason is if you step on a snake, it bites back and if you think about it, that’s at about calf-muscle level.
Out here you wouldn’t last more than 30 minutes from a really nasty snake bite, so we took the boot option.
The problem is we were wading through rivers, so every 10 minutes or so you’re carrying two extra boots of water – and trust me they’re heavy.
I was shown how to lean against a tree and bend my knee towards my back to empty the water. Simple, but annoying, although by now I accept the common wellie could really save one’s life.
Michael Zambrano from Venezuela is carrying his sleeping two-year-old son Lucien in a baby carrier on his chest, and a heavy pack on his back.
His four-year-old son Jordan sticks close by his parents. Mum – Mariangela – is seven months pregnant. They’re expecting a girl and have already named her Ana.
This family has been walking for months.
They left Venezuela seven years ago, lived in Chile for a while, then came to Colombia, where Michael worked as a street performer, making enough money to continue on their journey north.
The family are towards the back of the group.
“We have to save our energy and go slow,” Michael told me.
“I have this backpack plus my baby, so it is harder, but this one is four years old, so he is at least able to walk,” he continued, pointing to Jordan.
Every so often another Venezuelan migrant, Eduardo, who the family has met on the trail helps them, hoisting the little boy on to his shoulders in the deeper water.
Along the route are wooden signs nailed into trees urging them on.
One reads ‘Don’t be afraid’, another, ‘Difficulties vanish when faced with courage’.
But the jungle is full of deadly snakes, spiders and insects. It’s scorching hot and humid.
And very quickly the migrants start to thin out, the youngest and fittest leave the weakest ones behind.
The last of the group is a woman who has already sprained her ankle, it happened in the first hour.
She’s now using a stick for support. Her husband stops her every now and then and takes off her boots to empty the water and check the swelling. And then they carry on.
It’s impossible to imagine she will make it. But she keeps going.
They know they must climb the peak of at least one huge mountain, but the whole journey is arduous.
The rivers can surge if the rain is heavy, and that can simply wash people away to their deaths, especially if they can’t swim, which many cannot.
The first major test our group meets, after the river, is a high hill that is made entirely of mud and rock.
It’s steep and it’s like setting clay. The migrants have to get over this to continue their journey.
Simple wooden steps have been cut into the mud, with ropes to stop people falling into a ravine.
Without these steps their passage would take hours.
My wellies sank up to the top in mud as I hauled myself up. At the top a narrow gap has been dug between mud-covered rock that only one person at a time can pass through.
I edge my way through before descending the muddy staircase, slipping, and sliding, and holding the rope for dear life.
All I’m thinking is, if I’m struggling, how can someone carrying everything they own plus their children even remotely manage this?
And yet they trudge through the feet deep mud.
Some of the men grunt as they make their way up and then down the steep embankment, the women and children look terrified.
We meet Carlos Chinchin rinsing his boots and hands in the river water after getting through the muddy hill.
His toddler Carlito is strapped to his back, a Spiderman sun hat on his head.
Carlos is from Ecuador. His wife and their second child have already made the crossing and are in the United States.
I ask them where they are in the US, he says he doesn’t know.
“They’ve only told me they are in a shelter…” he replied.
It must be harrowing carrying such a small child through the jungle, but Carlos says he is driven by his desire to see his wife Catherine, and his child’s desire to see his little brother Josue.
As he sets off again, he sings to Carlito, calming him down, and comforting this little boy who can’t possibly know what is happening.
A few hours in we bump into Michael again. He looks tired this time – the family has just navigated the mud.
It’s hard he says but he has faith.
“There is nothing stronger than God, he will give us strength to cross all the mud ahead of us.”
It’s a remarkable amount of faith given the US border is now closed to Venezuelans.
The recent change in border policy means many Venezuelans are now stuck in countries along the migration route, unsure where to go.
Michael’s is one of them, but they are determined to carry on. He says he thinks the Americans will understand his situation and have mercy.
But they keep going. This is a huge movement of people which is only expected to increase.
And it’s hard to see how it will stop.
Dominique Van Heerden, Gustavo Aleman and Carlos Villalon, producers
Richie Mockler, camera operator