the following is a cnn special report.

>> so this is the rio grand valley? >> this is the rio grand valley. >> this is a common sight? >> this is the wall george bush built us. the fence. >> this journey across the u.s./mexico border begins in south texas where the rio grand empties into the gulf of mexico and on a rugged ride in an all-terrain vehicle with robert cameron. he runs an atv border tour business in the small town of progresso. do you think people have that impression of this scary dangerous place? >> absolutely. it's not as bad as people make it seem to be. >> cameron was born in mexico, now a u.s. citizen, was a long time democrat until donald trump came along and made him republican. he supports the idea of trump's wall but holes in the plan. >> is this secure to you?

>> m >> no, it's not secure. it helps funnel traffic here so you could monitor this area a little bit better. >> this fence cuts private property and divides it. what you see on both sides of this fence is still the united states. it's somebody's farmland. so they need to have access. you can't cut them off. >> you can't cut them off. >> they need to leave openings like this in the wall to give them access to their farmland. >> exactly, exactly. >> so when you look at this kind of wall, you like this kind of wall or you want to see something? >> i want to see a wall. this is fenced. i want to see a wall. i want to see something that you can't see through, you can't climb through. >> a few months ago, cameron recorded this video of what appeared to be smugglers with packs. it's the kind of story countless people along the border can share. >> this is exactly where they were coming from. >> you can almost see like a

worn out path. this is really thick brush. coming right out of the water. >> this is the route that they use to come across. and it's not just people. it's like, bundles with people. >> that's mexico there on the other side. >> so it's like, they made it here. now it's, get to the fence somewhere to cross and then from there, it's like, you still have a good mile to two miles to run. >> this is a great view of the river. >> this is an awesome view of the river. >> when a border fence already exists i this area y the flow of undocumented migrants continues. >> it hasn't stopped. absolutely not. >> stop over here. >> there's two. >> what are these? >> these are the ladders that the border patrol picked up. >> so you've seen it. there's a 10 foot wall. an 11 foot ladder.

>> exactly. >> how often do you see these ladders out here? >> this is a common thing here. so you've got this wall all the way around to the eye can see all the way around there. and keeps going. but then it's like, they start here? i don't know. i'm sure there's a reason. wouldn't you think? they ran out of money? >> some parts of the southern border are heavily fortified. in southern california, just north of tijuana, mexico, there is a double layer of fencing and now smugglers go where eyes and cameras can't see them. we are in a tunnel underneath otay mesa on the border with tijuana, mexico, a tunnel stretched into tijuana, or would have stretched into a warehouse on the other side of the border and we're about 70 feet

underground right now. >> that's one of the deeper tunnels we've ever found in there. >> known as the tunnel rats. they work underground, navigating newly discovered tunnels and sewer systems. >> do you think that these tunnels started appearing as a response as more fencing went up in this area? >> oh, i'm sure it probably did. but we're also still talking, there's a lot of stuff they have to move. >> homeland security officials say in the last ten years, nearly 30 of these tunnels have been discovered in the san diego area alone. >> they'll continue to go between the u.s. and mexican border, yes, they will continue. there's a way that these drug trafficking organizations can stay undetected and it's by tunnelling, they will. >> this is usually a high dollar, high risk reward enterprise. it's a lot of stuff they've got to move in a short amount of time. >> the north said the tunnels

are used to move large packs of marijuana and cocaine and lined with electrical power and ventilation. >> this one had a rail system many it. >> how long does it take to build something like this? >> depending on the resiliency of the digging crew, they can go really fast really far. >> by hand? >> basically almost exclusively by hand with power tools. >> what? >> something i don't try to second guess. i mean, they're incredible, some of the methods they used. >> fighting this eingenuity belw ground changed life on the border aboveground. this is the landscape in the big bend area of texas and that is the challenge. how in the world do you build a wall in this kind of terrain? >> the idea of a wall, how does that go over around here?

>> well, it's crazy. >> ready to roll? >> yes, sir. >> and we're out of here. >> beautiful. >> from a tiny airstrip in the far outpost of the big bend region of west, texas, marcus takes visitors on aerial tours of some of the most breathtaking landscapes you'll ever see. >> i have taken many folks that i think initially they went up with me and i think this notion of a wall was something they supported and then as we flew over this country, they realized, how are they going to do it? it can't be done. >> it's one of those moments i'm not quite sure the cameras can do it justice. so i want to know where in all of that do you put a wall? do you think donald trump flew in here? >> i want you to tell donald trump we don't really have a wall.

thank you very much. and i don't think he could build a bigger one. >> there we see the rio grand below us now. >> here's the rio grand into colorado canyon below us. >> that is a dramatic sight. >> we take a canoe ride on the rio grand through the heart of the big bend region. this is some of the most rugged terrain you'll find along the southern border. hard to imagine anyone would ever try to cross illegally through here. simply too treacherous. >> the big bend region stretches for roughly 250 miles along the rio grand, a place far past the middle of nowhere. you can hear the wind of flutter through the wings of coasting birds. one of the things that strikes you is just how quiet it is. and how far removed this area seems and feels like it's

removed from the intense debate of border security, immigration, the border wall. >> coming up -- >> the cartel, they're pushing through right now. >> a journey into the smuggler's trip. trade on a trademarked trade platform that has all the... get off the computer traitor! i won't. (cannon sound) i won't. ♪ some things are simply impossible to ignore. the strikingly designed lexus nx turbo and hybrid. the suv that dares to go beyond utility. experience amazing.

moving migrants come to life in south texas. nearly half of all the undocumented migrants caught by border patrol last year, apprehended here in the rio grande valley. tonight, a group of undocumented migrants emerged from the darkness and turned themselves in to local constables patrolling the park by the mexican border. [ speaking foreign language ] >> lopez escaped el salvador to cross the rio grande with tears

in his eyes. [ speaking foreign language ] >> this south texas shelter for migrants with border patrol. more migrants come from central america, not mexico. >> they are victims. they are suffering, and they need help. they started to come because of the violence and the violence escalated. lives, especially of kids, they are afraid that the kid is not going to come back from school. they're human beings. they're not illegal people. they're human beings that are asking for protection and we must not overlook that fact.

>> on the border's edge in mexico south of tucson, mai grants gather for breakfast inside a shelter known as the kino border initiative where jesus garcia is trying to figure out how to get into the united states, over a map, recounts how far he's traveled since he left home the day before donald trump was elected president. so he started here in honduras, made his way across guatemala, here in this little town and crossed into mexico. >> getting here has taken two months. for garcia, this map is a lifeline on his journey printed by humanitarian groups, the maps show the safest routes to cross through mexico and provides addresses of shelters that offer food and clothing along the way.

>> says he hasn't been able to cross. left home november 7th of last year and tried three times already to get across but hasn't been able to. garcia said it's first tim he tried and harder than he ever imagined. says, if i made it this far, i'm going to keep trying. father sean jaerl's mission to humanize voiceless migrants. >> i think there's a lot of fear and obviously, we need security. we need safety. but i don't believe that border security and respect for human dignity are mutually exclusive. we can do both. >> there is a struggle raging on the border. where does compassion end and security begin? >> oh, humanitarians. water droppers.

those are people with white guilt. they -- >> what do you say that? >> because, if you wanted to stop the flow by 75%, you could do it in a matter of two weeks by not allowing them to leave food and water out here. >> a legion of border patrol agents, ground centers are waiting. even some private citizens working on their own to stop migrants and drug smugglers from getting across. >> this is the scene in the matrix. >> in tim foley's world, the border lands are a threatening place. >> this is the red pill. this is what this world looks like. >> border recon controls around the u.s. mexico border with less than 100 people. >> i've been called everything

in the book. i've opinibeen called a domesti extremist. >> he said foley's group is made of native extremists. foley sees the flow of drugs, undocumented migrants and the wide open spaces of the border as the country's biggest threat. along the nearly 2,000 mile u.s. southern border, there is already 700 miles of fencing and barricades already in place. here in sasabe, arizona, the fence stretches several miles but approach the end of town, it abruptly comes to an end like these border fences often do as it stretches out into rugged terrain in the arizona desert. >> i put my cameras about 5 minutes from the road. >> foley relies on a collection of hidden cameras to capture movement of drug smugglers and often shares the information and videos with border patrol agents. >> unless you have people

watching the wall, it's not going to do anything. i mean, you'll see how desolate it is out here. you need boots on the ground. >> the group is armed and has detained suspected migrants for the border patrol. they say they only use force as a last resort for self-defense. right now, he's tracking what he systemati suspects is a group of drug smugglers f smugglers. >> it's the cartel. they're pushing dope through right now. but they're using a voice inversion, so you can't understand them when you're monitoring radio traffic. >> but they're close by? >> yeah, they're on that mountain right there. >> foley voted for donald trump and wants to see all undocumented immigrants who committed crimes in the u.s. deported but he's not convinced trump or anyone else can change the reality he sees. >> i want to be able to sit at

my death bed and not just say, what the hell did you do? at least i tried to make it a better place. and that's what i'm doing. >> finding a better place is what 18-year-old marcella is hoping to find. she was caught by border patrol with a group of migrants and quickly deported. she wanted to find work in the u.s. to help support her elderly parents. she trembles as she recalls the experience of being caught across the border. i asked if she was going to try to krcross again. she's waiting for him to get out and not sure what they're going to do next. >> the union representing border patrol agents to end the cycle, border security must come before immigration reform. >> the vast majority of people we catch are released because we let people that have broken the

law and that pose a threat to society into our neighborhoods and so we are looking forward to being able to make sure that they are removed from the country. >> we've had people come through here from every nation in the world. >> every night, 88-year-old pamela taylor out of compassion leaves bottled water outside of her home for migrants moving north and the border patrol agents chasing them. she's lived in this house in brownsville, texas, a stone's throw from the border since 1946. when the bordered fence was built north of the river, she found herself on the south side between the wall and mexico. >> you're a little bit of no man's land. >> my son-in-law said we live in a gated community. you have to laugh about it. >> taylor voted for trump and wants to see illegal immigration controlled.

she once found an undocumented migrant in her living room. >> donald trump wants to build this bigger, more powerful wall. >> i would like for mr. trump, i believe in freedom. if he'll come down here and talk to the people. >> until hethen, life on the border keeps passing by pamela's. take to the other side. top clic. the lowest prices on our hotels are always at hilton.com. so pay less and get more only at hilton.com. [bullfighting music] [burke] billy-goat ruffians. seen it. covered it. we know a thing or two because we've seen a thing or two. ♪ we are farmers. bum-pa-dum, bum-bum-bum-bum ♪

on this journey across the nearly 2,000 mile southern border, a park ranger in texas repleflected for a moment, it'st just one border but changes depending on where you are. this is true for 1200 miles, the rio grande carves an always evolving borderline with mexico. in some places, american and mexican cities like el paso texas and juarez, mexico, blend

together. give way to majestic mountain. and fruits and vegetables gives way to border fencing that rides the rolling sand dunes of the southern california. this is the end of the road where the border fence cuts just north of tijuana, mexico, and ends here in the pacific ocean. but while the physical landscape of the border might change dramatically, there was one theme we heard repeatedly on this journey. people who called the border home are bracing for the most dramatic changes they've seen since 9/11. >> we're an integrated dynamic community. but what we are seeing is there's a lot of tension, there's a lot of fear, there's a lot of uncertainty because in the past, when the border becomes a target, that's an excuse to increase enforcement, it means people who live on the border suffer. >> alicia and chris martin spent lives straddling both sides of the border.

they own organic farms and one of the most unique restaurants in logalas, mexico. >> it's called the rock. because your uncle built this into the side of this mountain. >> that's me. >> as a child, alicia remembers freely crossing the border into mexico. >> we come down in our bathing suits, by the popsicle, get the ice cream and go back. >> but with immigration control tightening on the u.s. side and the fear of cartel violence, la rocca has struggled to keep its doors open. >> somebody came in and hit the light switch and there was nobody. there was nobody in town, there was nobody on the street. >> difficult problems to solve, throwing up trade barriers, putting up a wall. there's such harsh approaches to the problem and once again, you're treating a symptom and not going after the root cause of the problem.

>> tighten border security quite like this place. bokias, mexico. one of the smallest legal border checkpoints you'll find. this is the bokias and big ben national park, literally two little boats and across. bokias is a small town of 200 people. its lifeline is the tourists that venture across the rio grande for the tamales at the restaurant. >> it's nice to live here. >> lilly runs the restaurant her father opened in 1973. but after 9/11, united states closed the bokias border krosing and the town slowly started dying. had to close. the entry point reopened almost 4 years ago and falcons is back. but lilja worries about donald trump's crackdown on immigration

and border security. >> if that border crossing goes? >> then the town, again, will be dead again. it would be hard. it would be very hard again. we wanted to go through again. >> it's a chance of taking this row boat to the other side that just might be the best $5 you'll ever spend. it's 3:00 eastern. i'm ana cabrera in new york. thank you for being here on a saturday. you're live in the cnn newsroom and we begin with the arrest of hundreds of immigrants in a string of raids across the u.s. immigration and customs enforcement agents known as ice agents targeting homes and businesses. half a dozen states this week. arresting at least 360 people. ice officials say these are part of rne