Reporter: Imagine 3,000 feet he air. . No harness net. St you and the mountain. Is the wod of free lo imbing. And inswod, one climber is ontop.alex hold. Ou're seeking perfection, free soloing is as close as you can GE Reporr: 33 yearsld he's broken recordsaround the world. Last year he set sign granite rock face in yosemiteational park El cap is the most impressive wall oearth. 3,200 feet ofheeranite. It center O rock climbinguniverse. Obviously I get inw est it all time work, you like to do that? Yes, Repter: Hc jrney is the subject of a new national geographic film, "Freee who Reay know exactly what he's doing ared out. Put that I B persct me if you can. A lot of people might know Y name, GHT have heard el cap before. It's 1/2 times as big. It's not just that Y're talking abouter size. Climbing up almostlat sheet of rock. Yso how farack would havto gh somethingan do? As a kid when I uld go camping, looking at the wa looksimmee, unfathomably GE. Itearso wrap around T idea of tt bei possible. A moment in 2015, actually the imagine this witut ro. Reporte he spentwo Y prepping, practicing the route Ros, every detail, every hand meticulously pland.onero move on the climb codertain death. Then you drive up off the left foo into the thumb press. That's the worstol enre route. St makes morns to dohe two-handedp because Yo jumping T a good something to catch Reporter: Inevitably ag to theess climb, cameras rolling. How much of that preparation was also getting used to camera crews? Oe actual day of the so W had all of refined our ocesses to the point it was sort of pfectly Repnd and filmmakingduo, it wasn't just a tal change, it was a personal one. I've bonflicted Abo shooting free because it's so dangerous reporter: The film pulls back the rain oe danger and the tension the endeavor. The foremost challengeri risk of death. A step back. We had to ansuestions for ourselves. Wwas the fst moral question you had? What's the effect of the filmmaker on thsubject? And ift causes H to aera rolling? Everybodyws what D if something goes G, who should ke call? And that wheelill get kicked into gear, and tell wh you know. All right. No mistakes tomorrow. How did you deal with T ques, can we liveith something happens? I ces down to that a life lived. I'mional climber. He mindset. We belien his ability to D it. But we a kw that if we were going th also had toecuteperfectly. Reporter: W trail, climber tommyld everybody whoasade free soloina big par O is dead I've h30, 4 friends that have died. You describe breaking handhold and a little slip. Those thingsld have resulted in your death. You ca ind conseqe. Yeah. Righ describe that. Explaithat to . I like separate risk and sequence. Consequence being,now wt will actuall H I you fall. People say that the fng is skwell, not allree soloinis risk some of it's asy asalking oe sidewalk it's all very high nsequence. Tt's what you do, you mitigate the risk as best you can? Cep ere, you feel pretty confident -- ah,ideally, I think that's part of the S taking something that seemsdamentally scarynd make it feel comfortable and control. Eporter: T film elores whether Alex is built difftly thanhe rest O, LE take the impossibly dangerous impossibly norther Normal. Several ex-girlfrie ended H personalities disorders and thgsike th is my brain inc? Your brain is intact. Youe no activation in your ygdala. Do you think it doesn't work? Yourgdalaworks. It jus a much gher level of station. Areypically sting for mos of use noty doing it for you. Toohat to mean T basicallov time I've sort of desense myself to a certain ulus. I've beenlimbing ove0 years. It used to be a lot things in climbing used to be more scary, and oveime I've used to it and now feel quite mfortable. Orter: Themotional toll in alex'sends and family in the leadup to E climb at times difficult to WATC pecially WHE comes to his girlfrndsoni Awesome, makes lifeter I every way. T's real Har fore to grasp why he wants this. Whatf something ens? Howidou ppare diently? Did you ft it was rent experience being in such aerious relations thimeound? The reason itt of worked T issoni, girlfriend, told youon to wi me to climb. First that hadlly been presented to me. Ly? N I do that? One par that outhen your girlfriend is sitting B herself in the car S. Why es he have T do is? That's hard to for sure. Iteaard to do something if you know THA somehat you care about deeply is G to be S by it. Certainly when I wathe film I'm ke, oh, I didn'tw it T HD for her. Reporter: In thegainst L odds, Alex overcomes hetache an injury and accomplish the impossible.and dn less than will you ever give up free soloing? Thought about retirement at Al yeah, if I'd never anhiore gra than el cap, I'll stillhonored. Is this thereatest feat ink --S. I think it's one of the gest any kind,r, really.ction or death. It's very unbeli. Youot a front rat for it. Ye Beaul. It wasbsely beautiful. Solo" isow in theaters.