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jcpenney, where giving begins. good evening. tonight we are going on a journey deep underground at the u.s./mexico border into the tangle of tunnels used to

high-level drug kingpins themselves. nearly 200 of these tunnels have been discovered and abc's matt gutman takes us for an up-chose look. >> repororr: in that beige garara is a multimillion-dollar hole in the ground. and 're about to stuff ourselves into it. my god, is it dark and chaus tro phone nick here. this is terrifying. we are the only news team ever to go down that hole. >> that's a spike my head nearly went through. >> reporter: crab-walking our way down a former drug smuggling tunnel between the u.s. and mexico, one of the ways that tensns of billions of dollars of drugs are trafficked into the u.s. every year. u.s. and mexican authorities have found and destroyed over 180 tunnels along this border. the question they say isn't whether there are more tunnels, but how many and where. much of what what's funneled

mexico's sin cineloaa cartel. thth leader busted out of prison earlier r is year but having h come raids tunnel right into his prison cell. a tunnel fitted out with a motorcycle on a rail. notorious not only for his narrow escapes and prison breaks but for the elaborate cross-border tunnels his cartel has engineered. some like this tunnel discoverered near san diego, thousands of feet long. the job of finding them goes to the human moles, the customs and border protection tunnel am. >> you g gs took the training? >> r rorter: tasked withh the somememes deadly job of sniffing out the tunnels honeycombing the 2,000 mile long borr with mexico. >> what's crazy is that there's a tunnel right here and then there's a tunnel 20 feet behind. three tunnels within the space of a year in 15 feet. >> correct. >> reporter: out of the 180-some tunnels found along the border

in the city of nogales. dodons within a football field d of where we're standing. >> concealing methods are creative. it's creativity. it's that simple. >> reporter: those engineers also use the massive drainage system between the two sides of the border. >> right here is the tunnelling attempt. they chipped this wall out and crawled through here with the bundles and followed the wall around the bend, through the double gates, then they came out in the pipe north of the north gate. >> reporter: detecting them isis nearly impo upon. the one here in arizona, a retirement community carved neatly into the floor of a garage along this quiet street. >> looking at this house, would you ever think that there's a highly sophisticated tunnel right through there? >> you could drive by it a million times and not have any clue. >> reporter: topping off this ruse is this engineering gem. a trap door operated hydraulically from 1,000 feet away in mexico. it's perfectly camouflaged with the garage floor. before we duckk in, the one

>> the rule is not to touch anything. because it's caving in behind you and there's no way back out. >> reporter: once inside, the air is in short supply. so they have to pump it in. and what little air there is feels syrupy. >> cockroaches? >> we have cockroaches too. >> reporter: it only has to be comfortable enough to do one thing, smuggle drugs fast. those sacks, that's got to weigh 50 to 100 pounds, eve one of those things. theyeyaul them all the way back through? >> correct, t ty drag them all wait back. >> reporter: dirt goes out and drugs go in. >> if you do a 4,000-pound wad of marijuana that pays for the tunnel? >> pays for the tunnel easily. >> reporter: dug by hand by day laborers, working with simple tools, for almost no money. no one knows how many tunnel diggers have died down here are. when diggers survive they often thank the tunnel gods. >> wow, that's interesting. >> a lot of the tunnels they tunnels. they vary. sometimes they're just stuck in

the mud. >> reporter: in our hour inside the tunnel there's some fear it could cave in. >> you can see the plywood creeling on here is all just rotted away. it caved in. right now just walk right here. walk gently through here. you don't want to touch the walls or anything. >> reporter: we see artifacts and what passes for entertainment. finally we reach the end. at the end we'd be under the fence. >> reporter: theheunnel had been filled in on the mexican side we hoped to see it but we're told the mexican government was too busy toee us. >> you made a mistake and the attorney general's office couldn't give us permission outside of the house. no one from the institution could go with you form. >> reporter: turns out you're agents were in hot pursuit of el chapo and we'd have to fend for yourselves. that morning we e t a call. >hey're willing to helel us out. the officer of one of the prosecuts there is going to meet us. >> okay.

>> reporter: our convoy rolls up to a gated house. it's blocked. and someone scampers off to find a key which in this case turns out to be bolt cutters. inside the house is a mess. a labyrinth of sodden clothes and leftover food. >> still the hot sauce on the tablbl the tortillas as well. maybe what's most amazing about this tunnel is a family used to live in that house. there are children's toys and clothes. and yet in the backyard here, there was a massive piece of construction going on. that hole goes down about 25 feet. it's lined with concrete and cinderblocks. in order to dig that tunnel, 900 feet that inn that direction they had to remove hundreds of tons of dirt. yet the n nghbors say they saw nothing and heard nothing. i asked the mexican officer with us who built it?

el chapo? >> reporter: he said he doesn't know. it was abandoned when they got there. >> right at the end of this street, just four blocks that way, is the u.s./mexico border. that right there is the border fence which means thatt that tunnel was dug right underneath the noses of body u.s. and mexican authorities. following the line of the tunnel above ground, supervisory border patrol agent tom pittman admits that's probably true. customs and border protection has robots they insert in the tunnels. this is one of those robots' view inside drainage pipe used to smuggle drugs. because of the tools and debriss so often left in t tse tunnelsls the robobs often snag and get stuck. they tell us there's no technological solution on the horizon either. what they knoo is that when they find a tunnel they know ty have an exit point and there's only one way to find out its entry. >> so basically the technology that exists today is the same that existed 50 years ago when

dealing with these tunnels? >> one of us that can fit will go in there without anything on, just a pistol and flashlight. >> reporter: and hope he doesn't find someone elsls in there. forr "nightline," i i matt gutman in nago, mexico. and up next here, how julia roberts got the starring role in "secret in their eyes," a role originally meant for a man. also how she made our michael strahan blush. >> i like it! welcome to the most social car we've ever designed. the 2015 nissan murano. recipient of autopacific's best-in-class vehicle satisfaction award. now get great deals on the nissan murano. i tried depend last weekend. it really made the difference

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julia roberts has been churning out box office hits since the 1980ss, earning the titie of "america's swee heart." the latest l lding a role written for a man. abc's michael strahan spoke to julia roberts abou her new movie and what makes her happy. >> i don't have the stomach to watch him walk away again. >> reporter: from america's sweetheart to a meertsd seeking revenge in the new thriller "secret in their eyes." >> i found martin. >> reporter: julia roberts plays an fbi agent investigating her own daughter's death.

>> it's carolyn. >> what? >> it's -- it's carolyn. it's your daughter. >> repter: it was an intense role -- >> help me! >> reporter: roberts had spousal support on-set. danny moder, the film's cinematographer and her husband of 13 years. >> did it help to have him there whenever you got out of a heavy scene? >> it helped if a couple of ways. because first of all, i try to impress himo much that really, as much as i t t to impress my director -- >> really? >> i think, is he? okay. >> are you trying to impress your husband? >> of course. he's my person. >> i love that. >> he's my person. in that regard i think i definitely tried to go more, find more, to kind of make him go, i did not expect her to do that. it became very meditative to go to work together or come homee togetherernd we've kind of gone through -- we come home, how was your day? well, we did this, this.

none of that. it was all about the kids. which was amazing. >> reporter: over her nearly three decade long career, roberts has played it all. from a law school student in "the pelican brief" to a maid of honor trying to steal the groom in "my best friend's wedding." >> i dreamt some psychopath was trying to break the two of you up. reporter: she won a a oscar for playing a passionate activist "erin brockovich." >> not personal? that is my work! my sweat, my time away from my kids! if that's not personal i don't know what is! >> reporter: it was her role as a pretty woman that catapulted her career. >> oh! >> reporter: 25 years later, i met up with robert in the same place where she shot "pretty woman." the beverly y lshire holt. hotel. >> wow. >> do you have any feelings that

come over you when you come into this hotel? >> abject awkwardness. especially when i go into the elevator. because the elevators are exactly the same and have the little seats. >> color me happy there's a sofa in here for two! >> first time in an elevator. >> reporter: that's when i just walk in and kind of look arou. everyone's looking at their feet. >> because you make them neneous? >> because we all feel uncomfortable. >> you don't make me feel uncomfortable. >> if we g in an elevator you'd be so uncomfortable right now. >> don't you ever, ever -- >> reporter: in "secret in their eyes" roberts played a role originally written for a man. >> when they say, we want you to play this part. they don't want you to play it as a man. i've had too play oprah so i'm curious. they made me play y rah as a woman. >> i do feel masculine, i'm a manly girl. it was one of those things they

original and incorporated some issues, some situations from other characters, in the original, to put together to create the character that ultimately i do play. >> reporter: despite her superstardom roberts prefers to stay out of f e spopoight and off social medidi instead focusing her attention on her three children. as the father of four kids myself i was excited to ask her for parenting advice. >> my daughter said to me last year, talking about school, and she was having some frustration. and she said, mommy, you just don't know what it's like. the next morning i said to her, guess what i'm going to do today? i'm going to sit in the back of your classroom all day today and understand what it's like. >> wow. >> by the time the belll rang to go home, this is what i know. no child wants to get in the car and have their parent say, how was your day?

>> so you were overwhelmed by it? >> i just -- i just wanted it to be over. >> all i can say is, it was a quiet car ride home? >> and that's okay. that's okay. to not be talking i ithe car? is fine. >> i like that advice. >> reporter: roberts said she leads a normal life. cooking, helping her kids with homework, walking the dogs. she even let me in o one of h family traditions. >> there's something i hear you play at the dinner table, the family dinner game. >> the family dinner game. >> you ask questions around the table. can we play that? >> do you have questions? >> i have a few questions. >> what's your middle name? >> anthony. what is the first thing you look at when you see somebody? >> i guess - - you know, your eyes, your smile. probably your eyes. they're brbrn. they're twinkly. >> i'm blushing. i didn't think i blushed. >> they are brown and twinkly. >> brown and twinkly, okay, thank you. >> that's when you say, oh, so are yours. >> reporter: looks aside, i asked her about her key to happiness.

>> you have the natural chemistry of joy. what is the natural chemistry of joy? >> just -- a roll of the dice, i think. i feel like i was born of joy. and i know that you share that same feeling. that just happy is something that i feel i'm blessed with o there's also that sweet adage, it doesn't matter if you win or lose -- until you lose. >> oh. >> i'm just kidding, that's not -- >> i kind of liked i i was mesmerized. oh, boy!y! oh, that was pretty good. >> thanes to michael strahan for that report. up next on "nightline," would you hit the slopes after surviving this why and how this guy managed to walk away unscathed. (under loud music) this is the place. their beard salve is made from

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a professional skier gets back on the proverbial horse just two days after a heart-stopping video. how did he pull it off? here's abc's t.j. holmes. closely. >> oh! >> reporter: that's professional skier ian macintosh plummeting 1,600 feet with theounds of every painful bump and grunt recorded on his way down. >> oh! ! it felt like an eternity.p it really did.

to stop. >> reporter: macintosh was filming "paradise waits" when he mistakenly skis into a five-foot trench and wipes out. >> oh! oh!! >> i had no ideaeahat was coming. i knew at that point it was game over. i was going tort ride of my life. >> reporter: that's the very moment you hear him cry out. >> oh! no! >> it felt like i was getting hit by linebackers the whole way down the mountain. over and over and over again. >> reporter: while macintosh was falling he was thinking. he made the decision to deploy the avalanche air bag that was built into his backpack. >> pull that white handle for me right there. there's your life jacket. for when you're flying down the mountain. >> you're thinking all these` things while in a death spiral. >> to do what i do for a living you don't panic when things get

nearly a minute, macintosh comes to a stop. >> i'm okay! >> reporter: miraculously, macintosh was able to walk away unharmed and undeteteed. >> these air bags are designed to keep you on the surface so you won't get buried in an avalanche. i don't want to die doing what i'm doing. i don't have a death wish, i'm not the type. but i do have a wish to live life to its fullest and get out there and live my dreams. and this kind stuff is what i dream about, it's what i lay awake thinking about. >> reporter: for "nightline" i'm t.j. holmes in new york. our thanks s t.j. holms and our thanks to you. tune into gma first thing in the morning and don't miss diane sawyer' interview wi the star of "the hunger games" jennifer lawrence tomorrow. we're always online at abcnews.com and on our