tonight on "nightline," he was the most famous face on the milk carton. a 6-year-old boy who disappeared on his way to school. one of america's most famous cold cases, now more than 30 years later, police finally make an arrest. we tell you what they think really happened to etan patz. dangerous game. hit after hit in game after game. the invisible head injuries causing widespread concern in the nfl. and tonight, growing concerns at high school and pee wee players could be at risk. the hidden danger that even helmets can't prevent. plus, we meet three pals who hit the open road, crossing four continents and 50 countries, all in a world record taxi ride.

>> announcer: from the global resources of abc news, with terry moran, cynthia mcfadden, and bill weir in new york city, this is "nightline," may 24th, 2012. >> good evening, i'm terry moran. 33 years ago tomorrow, 6-year-old etan patz vanished while walking to the school bus. for decades, the search for etan and whomever abducted him was never put to rest and it helped ignite the national movement to find missing children. well, tonight, a major break in this case, as police announce that has confessed to his murder. finally, it seems, his long suffering family may find justice. here's abc's david muir. >> reporter: tonight, nearly 33 years after that little boy, 6-year-old etan patz, disappeared on the walk to his school bus, a break in the case. pedro hernandez is under arrest for murder, seen here in this "inside edition" photo of

hernandez. hernandez allegedly confessing to police he was the one who stole that little boy on that walk to the bus. >> we believe that this is the individual responsible for the crime. >> reporter: the day etan patz disappeared was the first morning his parents let him walk alone to the school bus. the suspect, pedro hernandez, now 51, was 19 at the time. allegedly telling police he lured the boy away, just steps from the bus stop, promising him a soda at the small corner store where hernandez worked. >> he then led him into the basement of the bodega, choked him there and disposed of the body by putting it into a plastic bag and placing it into the trash. he had worked as a stock clerk in a bodega for approximately one month. >> reporter: patz was among the first of the missing children to appear on a milk carton. the face that changed the way parents across this country sent their children off to school. police say there is now a

written and signed confession, a videotape, too. a tearful 3 1/2 hour confession. more than three decades later, authorities believe they have their man. >> he was remorseful and seemed to, i think the detectives thought that it was a feeling of relief on his part. >> reporter: that small corner store, just a block and a half from etan's home, where all these years later, a high end store selling eyeglasses now sitting in its place. hernandez was picked up in new jersey, where he lives with his wife and daughter. this is just a month after the fbi and new york city police returned to that same walk to the school bus, digging in a basement of another building etan walked past that morning. they were looking for human remains in a celler where a handyman once worked. but they found nothing. abc news learned that it was the attention that led to a new tip. it is believed a member of hernandez's own family or friends called authorities, saying, you should take another look at hernandez.

>> in the years following etan's disappearance, hernandez told a family member and others that he had, quote, done a bad thing, and killed a child in new york. >> reporter: etan patz's parents were told of this break in the case before tonight's arrest. it was etan's mother who last saw her son on that short walk to the bus in 1979, standing at the front door of their building and seeing him off. author and generalist lisa cohen wrote the book kwf after etan." >> he turn and walked a block, crossed west broadway and the bus stop was right here. >> reporter: so this is a block and a half block? >> yes. >> reporter: a block and a half and for that 6-year-old, about 223 steps to that school bus. >> his mother could actually see children starting to line up to get on the bus. >> reporter: she saw him off that morning, went inside and never saw him again. etan's parents still live on that same block, never changing their phone number, never moving. the little boy's father telling

abc news just three years ago that he and his wife always held out hope their boy would one day come home. >> we didn't know what had happened to him. we didn't know where he might be. so, of course, the thought in the backs of our minds was always that we should be here for him. >> reporter: that father, still haunted by what his son must have faced. >> i still gag with the fear that this child must have felt. when he realized he was betrayed by an adult. >> reporter: that tragic walk changing the way a nation searched for missing children. those milk cartons, the billboards and today the instant alerts. >> etan's case was a case that changed america. millions of parents sat at home and thought there but for the grace of god those my child. >> reporter: it was then president reagan who first declared national missing children's day to mark the day etan disappeared. tomorrow, this country will mark that day again, 33 years later, to the day. as etan's parents now learn of

an arrest, a confession from a man who says he stole their child, 33 years after etan left for school. i'm david muir for "nightline" in new york. >> and so that long and agonizing search may finally have come to an end. thanks to david for that. up next, well, their helmets won't help them. the hidden head injury danger that doctors say is putting even the youngest football players at risk.

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>> announcer: "nightline" continues from new york city with terry moran. >> since the days of leather helmets, football has been one of america's most vigorous and violent past times. but there is a hidden cost to

playing the game and concerning growing about the long-term effects of invisible brain injuries and it's not just the nfl stars who are in danger. some doctors say it's even the youngest players. a revelation that has many parents asking the question, should you let your kid play football? here's abc's paula faris. >> reporter: friday night lights. families lining the stands at football fields across america. to cheer on their boys. but what if every one of those k hits are leaving these teens with a traille of invisible head injuries, like the ones suffered by owen thomas. >> i mean, he just lived for football. he just couldn't wait. he said, i can't wait to hit somebody. >> reporter: owen was the captain of penn's football team, a third generation college athlete. his parents say football with his his blood. how old was he when he started playing football? >> well, we postponed that as long as we possibly could but owen just pestered us. he wanted to play. >> reporter: and he was happiest when he was with his team.

>> he was very outgoing. he had a lot of friends. and he was popular with the cheerleaders. >> reporter: which is why it came as such a shock when owen, just 21, killed himself. you could never fathom that your son was capable of doing something like this. >> i thought, there has to be some reason behind this. >> reporter: they were still driving home from the hospital when they got a call from the sports legacy institute, asking if they could study owen's brain. >> when they asked for his brain, i said, well, he never had any concussions. i didn't think they'd find anything. i was sure they wouldn't find anything. but i thought, well, we'll do what we can to help the research, whatever. i was just astounded they found cte. >> reporter: cte, or chronic traumatic encephalopathy is a brain disease linked to similar on toms like demen ya, and yes, suicide. doctors have detected it in dozens of now dead nfl players.

but the discovery of cte in owen's brain makes him one of the youngest players ever to be diagnosed. >> i would say it was the straw that broke the camel's back. i think if he didn't have cte, he would not have committed suicide. >> reporter: and indeed what's happening inside the brains of the game's young athletes is at the center of a heated public debate. not just about professional football but players in high school and even pee wee leagues. a string of big football names including former nfl player kurt warner and the father of super bowl champ tom brady have said learning about cte has made them reconsider whether they would have allowed their own kids to play. the recent suicide of long-time nfl star junior seau has caused a lot of current players to think different it will about the cost of playing the game. >> the san diego native became the charger's hometown hero. >> reporter: seau, a famously hard-hitting linebacker, was an nfl legend. his death left many wondering if

cte was to blame. >> seau's death rocked me a lot. >> reporter: for jacob bell, it was a tipping point. until a few years ago, he had been living a dream, making millions playing professional football. >> you know, to be a gladiator with everyone in the arena around you, cheering for you, you really do, you know, donate your life to the game. >> reporter: but he knew that glory came at a price. do you have any health concerns? >> absolutely, yeah. i think anyone that would say that they played eight years in the nfl, didn't have a health concern, would be lying to you. i'm concern and my mental and brain health. >> reporter: and so earlier this month, he quit the nfl. walking away from a free agent contract with cincinnati. >> eight-year career, five years i played in college and all that i played before that. to think how many compounding small concussion hits you've had that you may not have felt, you felt a little bit. it's too hard to count. it's in the thousands. >> reporter: but it's not just

nfl players who are taking thousands of hits to the head. one study found that a football player can sustain 8,000 head impact s by the time he finishe his college career. so, the question now is whether the cumulative effect of those lesser hits is enough to cause cte. >> how much of that is occurring, we really don't know. >> reporter: doctor julian bailes is a neuro surgeon and one of the leading researchers on cte. >> we've autopsied several former football players, who had cte, who did not have a history of concussion. they didn't have it. it means that the issue of sub-concussive blows, where an impact is there, doesn't reach that diagnosis of concussion, may loom as an issue. >> reporter: dr. bail eles was e a college football player himself. >> i played football ten years. i think it's america's greatest sport. we're at a cross roads now. >> reporter: he says the way forward isn't a new helmet.

>> a lot of the hall melts are safe. they are good. but there's not a concussion-proof helmet. >> reporter: but in rethinking the way the game is played. >> i think at every level, from professional down to youth, we have to take head contact out of the game. >> never, ever come into your opponent with your head down. >> reporter: he introduced us to his friend, former chicago bears trainer mike cordecky, who is showing these young players how to play in a safer way. >> go! good, good, heads are up. >> reporter: next month, pop warner, the nationwide youth football league, will make moves like this standard. in a major effort to make football safer for developing brains. >> if owen knew the dangers of cte, would he choose to play football? >> reporter: what do you think the answer is? >> i think he still would. >> reporter: jacob bell also says life in the nfl was worth the risk. >> are you still going to play the game knowing what you know? for me, i would have still played. i would have still done it.

>> reporter: he now wants to take on a roled a an advocate for players, alerting them to the dangers of cte. that's a way of keeping his heart in the game and his head out. for "nightline," i'm paula faris in los angeles. >> well, the nfl released a statement in february, saying that the league, quote, has long made player safety a priority and continues to take steps to protect them and advance the understanding of concussions, unquote. thanks to paula farris for that. just ahead, we're going to meet three buddies crossing the globe in a record-breaking taxi ride. the wheat in every mini-wheat has gotta be just right.

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it ended as a 15-month record-breaking journey that crisscrossed the entire globe and it all took place inside an old taxi cab. abc's t.j. winick met up with three pals at the end of a big adventure in the busiest intersection on earth, right here in times square. >> reporter: what do you get when you take three college buddies, a night of drinking at the local pub and a whole lot of wanderlust? how about the longest, most expensive taxi ride in world history? meet john-o, paul and lee. not since the beatles has a british invasion covered this much ground. >> made it to turkey. next stop, istanbul. >> reporter: more than 43,000 miles, four continents and 50 countries. not just in any cab, a 1992 london black cab. >> if you want to pick the car that you least want to drive around the world in, it's this one. >> reporter: in a year, they've driven to mt. everest -- >> oh! >> reporter: dodged rick shaws

and livestock in india and smashed a windshields or two. >> oh! how did he do that? >> reporter: i caught up with the guys for their toughest challenge yet, navigating me through the mean streets of new york city. there's a certain smell in this cab. what exactly is that? >> that's my teammate. a combination of him and diesel and oil and a year's worth of dirt and grime and living in this car. >> reporter: that idea first dreamed up after a night out on the town. >> we were in the back of a taxi. we were looking at the fare, and we thought this is one of the most expensive rides ever. it came from there, the idea to break the record. >> reporter: and you gave this cab a name? >> yeah, this cab is call ed hannah. ♪ they call her hard-hearted

hannah ♪ >> she's a gal that likes to see men suffer. ♪ she's a girl who likes to see men suffer ♪ >> she's made us suffer a lot. she's lived up to her name, i tell you that. >> reporter: she's been stuck in the mud in indonesia. hassled by the military in china. and what would a road trip be without a few detours? in fact, they were forced to drive 1,000 miles out of their way to avoid the middle east during the height of the arab spring. >> we are just approaching the new world record for longest ever taxi journey. >> two, one -- >> hey! >> that's in pounds. that's the meter. we've had it on the entire way. >> reporter: besides finding a bed, these four wheels have literally been full. >> you fried meat in the backseat here? >> while well were driving, 60 miles per hour, bacon. the car stunk really bald after that. >> reporter: which didn't help matters anyway. after all, it can get lonely out

on the road. how is this cab as a chick magnet? >> well, you smelled it, so, maybe not really. >> reporter: but these guys aren't totally out for themselves. they raised over $31,000 for the international red cross. >> wow. >> cool. >> reporter: hannah remains a curious spectacle, no matter what continent she's on. would you ride in the back of this cab? ♪ that's hard-hearted an eed h♪ >> reporter: true, you're not winning many style points, but the journey to happiness may have just begun, now that they are back to england. >> if i never see another taxi the rest of my life, i think i'll be a happy man. >> reporter: for "nightline," i'm t.j. winick in new york. >> congratulations to them. thank you for watching abc news. we hope you check in for "good morning america." they aic