this is "nightline." >> tonight, it's tbeen more tha half a century and now the u.s. ban on cuba is finally lifted. changing history for two countries overnight. our david muir with president obama, facing hard questions. why he believes will be generational change and the unlikely negotiating role played by the pope. >> he is the real deal. plus, she was sent to prison for the death of her foster child, but tonight, this convicted mother is released at last. and we are there as she takes her first steps towards freedom. after a seven-year battle, is another ahead? and heels up. >> three -- >> our michael strahan is rocking it with the rockettes. can this former nfl player pull off a kickoff line like no other?

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protected. given new hope. during the subaru "share the love" event, subaru owners feel it, too. because when you take home a new subaru, we donate 250 dollars to helping those in need. we'll have given 50 million dollars over seven years. love. it's what makes a subaru, a subaru. ♪ ♪ good evening. this has been an historic day, as president obama announced the u.s. will restore full diplomatic relations with cuba.

suddenly, the ban lifted, and the pope played a major role. but not everyone is celebrating. our david muir sat down with the president at the white house today to find out why. here now with the full story, abc's senior national correspondent, jim avila from havana. >> reporter: after five long years in a cuban prison, american contractor alan gross is suddenly a free man. >> it was crucial to my survi l survival, knowing that i was not forgotten. >> reporter: spirited out of havana aboard a government jet, in a deal that could change history. in this video, provided exclusively to abc news by senator jeff flake, who was on board, allan gross peerm peers window at freedom. and then -- >> u.s. air space. >> reporter: and the actual reunion with his wife judy, who flew to cuba along with his

attorney. his first words, simply, "i'm free." >> today is the first day of hanukkah, and i guess so far, it's the best hanukkah that i'll be celebrating for a long time. >> reporter: his release was the final condition in a year and a half of secret negotiations. now, for the first time, in more than a half century, president obama acted to restore full diplomatic relagtss with cuba, installing an embassy in the isolated socialist nation. which could open the door for trade, tourism and american investment. >> neither the american nor cuban people are well served by a rigid policy that's rooted in events that took place before most of us were born. >> reporter: tonight, in new york, a group of young cuban-americans gathered to celebrate and debate that historic moment. >> the reality is the basic freedoms that we all enjoy in countries like the united states, those basic freedoms aren't given to cubans on the island. >> reporter: nathalie grew up in

florida. like most first generation cuban-americans, she supports the decision. >> i'm very hopeful about what this means in terms of our abili ability. >> reporter: to understand and respect the fact that their parents and grandparents may remain strongly opposed. miami radio host is an outspoken cuban exile who broadcast on radio mambi. >> this is the worst message that president obama could have sent, not only to the cuban people, but to the administration. and the people inside cuba, members of the opposition, feel the same way. >> reporter: her sentiments are echoed by prominent cuban-american politicians on both sides of the aisle. >> this undermines our moral credibility at the leader of the free world. >> if this administration takes cuba off the state sponsored

terrorism, what a message we're going to send. >> reporter: but despite that criticism today, polls show that a majority of americans, even of cuban-americans, now support more open relations with cuba. >> we look forward to getting back our -- a lot of our cuban heritage and going to see our family will be easier. >> reporter: and here in havana, bells rang askew ba witnessed something people here thought they might never see. presidents from the u.s. and their home island agreeing on the future. do you think more americans coming here will be good for you, good for cuba? >> of course. >> reporter: because? >> tourism. tourism. >> reporter: money. >> of course, money. we need money. >> reporter: "world news tonight" anchor david muir spoke exclusively with president obama about earlier today. >> well, i'm not sure that, you know, raul castro at the age of

80-something is going to be changing significantly. but there's going to be generational change in cuba. this last conversation was substantive and the point that i made to mr. castro was that given the proximity between the united states and cuba, given the strong family ties between the united states and cuba, there should be a way for us to move the relationship forward. i was very insistent with him that we would continue to promote democracy and human rights and speak out forcefully on behalf of the freedom of the people of cuba. >> reporter: officials say the ailing contractor, alan gross, was released on humanitarian grounds. but the u.s. also negotiated a prison swap today. releasing three cuban spies for one of our own. held in cuba for 20 years. a deal the pope helped broker. >> how crucial a role did the pope play in all of this? >> he played a very important role. when i had the meeting with pope

francis for the first time, back in the spring, this was one of the items on the agenda. >> reporte >> will you visit cuba? >> i don't have any current plans to visit cuba. >> not ruling it out? >> let's see how things evolve. >> reporter: the u.s. and gu have a long, contentious history that began at the height of the cold war. first, the bay of pigs invasion, and then, brink of nuclear disaster during the missile crisis. >> this is a cuban patrol boat. we are on it with fidel castro. >> reporter: abc's barbara walters was inside enemy lines while fidel castro was still aligned with the soviet union. >> mr. president, when will your country and my country have normal relations? >> translator: i believe that that depends on the good will of both parts and i believe it also depends on time. >> reporter: since then, cubans have suffered under economic embargo and weathered many political crisis, including the fight over little elian

gonzalez, whose mother was one of tens of thousands of cubans who resorted to rafts to escape extreme poverty. but desite this relationship, this island, only 90 miles away has retained a romantic hold on americans, who, for generations, have dreamed of returning. >> cuba is a real place. it's not just this place where my family suffered or, you know, it's not just about righting past wrongs. it's a real place where real people are living their lives today and i think we need to take that into consideration that it's not just about us. it's also about them. >> reporter: a new generation of cuban-americans who, like many here in havana, look forward to a new era. for n unti"nightline," i'm jiav next, will this mother finally released from prison after being convicted of murder make it home for the holidays? her emotional journey. and later on "nightline," what could intimidate former nfl

great michael strahan? could it be a line of dancers?

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tonight, a major twist in a case we've been reporting on for six years. hannah overton is a mother of five. in the eyes of the law, she was also a murderer. spending years in jail for the bizarre death of a boy she was trying to adopt. but now, the conviction has been overturned. "nightline" co-anchor juju chang has been on this story from the start as was with overton as she began her journey home. >> somebody's worst nightmare, after your child dies, to be

told that somebody thinks it's your fault. >> reporter: hannah overton convicted and sent to jail for the murder of her 4-year-old foster son. behind bars for the past seven years. yet, all along, she's maintained her innocence. did you mean to kill andrew? >> no. >> reporter: but what's happened since her arrest has turned into a long and twisted fight for freedom. >> i'd never hurt a child. never. what are you looking for, andrew? >> i'm looking for that. >> reporter: little andrew ended up apart of hannah's family after a troubled infancy. born to a meth addict, abused and placed in foster care at the age of 2. at the time, hannah and larry overton, former missionaries, had four biological children all under the age of seven. even as thhannah was expecting fifth child, they volunteered as foster parents. >> it was exciting to give that love to somebody who needed it. >> reporter: within a few weeks of moving in, hannah and larry began to see odd behavior. >> i started noticing that he

was hording food. anything that he found, he would put in his mouth. he ate dog food, cat food. >> reporter: it only got worse. obsessing eating. excessive tantrums. just four months after andrew moved in, another unusual tan trem. >> he was throwing a fit for quite awhile and then he threw up. >> reporter: when the 4-year-old complained of being cold and started shaking, hannah says she and her husband suspected the flu. when his condition got worse, they raced him to the hospital. >> within yards of the urgent car saecenter, he stopped breathing. >> reporter: andrew had salt poisoning, with a sodium level almost double the norm. >> i've never seen sodium that high in anyone. if you take salt at a level faster than your body can remove it, your sodium level will go up. it can cause brain swelling and come you have shuns and event l

eventually death. >> reporter: after two bowls of soul, andrew wanted more. instead, hannah offered him a sippy cup with water with a few sprinkles of seasoning. >> so, my thought is that i would calm him down, appease him. give him like a broth. without giving him a tummy ache. >> reporter: but that story didn't add up to the medical staff. one doctor calculated it would take 23 teaspoons to get andrew's sodium level that high. the day after he was admitted to the hospital, andrew died. >> we had been told that we wouldn't come back to the hospital, so, we -- we sent my mom and my step-dad and my pastor up there and they sat with him. >> reporter: both hannah and larry were charged with capital murder. automatic life sentence. the authorities quickly began weaving a sinister tale of murder. >> andrew had an enraged mother

who didn't, i don't think, love him the way she loved her own biological children. >> reporter: at trial, the prosecution suggested that despite her calm demeanor and no prior history of violence, hannah had turned abusive, forcing andrew to eat a toxic dose of that seasoning. but the defense had a different theory. that andrew might have had pica, a strange eating disorder marked by an obsessive appetite. did you force feed him salt? >> absolutely not. >> reporter: did you force feed him the seasoning? >> no. >> reporter: who would the jury believe? >> we the jury find the defendant hannah overton guilty. >> reporter: hannah was given a life sentence. larry later pled no contest to negligent homicide in return for probation. hi, hannah. nice to meet you. in the six years since "20/20" has covered her case, the

devoult mother of five has remained steadfast in her faith and confident her conviction would be overturned. her new defense team finally won a new hearing in 2012. at the center of the appeal, two doctors who believe in hannah's innocence, but never got a chance to take the witness stand. first, dr. edgar cortez. insisting that his concerns about andrew's health were ignored by the prosecution. >> i'm the one that felt that he hate other kinds of neurological problems. >> reporter: and then, dr. michael moritz. he told the appeals court exactly what he told abc six years ago. the most likely scenario was that andrew ingested the salt all on his own. >> i think most people would never suspect salt poisoning, since it is something very few pedestrians have ever encounters. >> reporter: despite their testimony, hannah didn't win her appeal. but just this past december, the break hannah's team had been praying for.

texas' highest criminal court reversed hannah's convict, granting her a new trial based on ineffective council. just a week after the good news, we visited hannah once again at her texas prison. >> i just want to khug my kids. >> reporter: you haven't been allowed to do that for seven years. >> yeah. >> reporter: she missed so much. the baby girl born just prior to hannah's try, who she had been nursing, is now a 7-year-old. their oldest son is now a teenager. hannah's girls are now 12 and 13. sebastian, just 3 when his mother left, is now 10 and clearly feeling the emotional weight of his mother's absence. tell me, what's been the hardest part about all these years waiting for her? >> not being able to spend time with her. >> reporter: late yesterday, a

judge set hannah's bail at $50,000 and ordered her to be released. hannah emerged from this elevator -- greeted first by her moth mother, then into the arms of her two eldest children. a few moments later, hannah finally able to embrace the other three children she hasn't touched for seven years. but their reunion is tinged with sadness. she still misses an true and says she has no regrets about trying to give him a forever family. >> i wouldn't trade that time that we had with andrew for the world. >> reporter: while the prison bars are now gone, hannah is not completely free. rather than dismiss the charges, a new prosecutor continues to believe hannah overton is a cold-blooded killer. and is planning to try her again for capital murder. >> make sure to tune into "home

for the holidays" on "20/20" next friday, right here on abc, for the full report. coming up, our michael strahan once played in the nfl. and tonight, he's working up a sweat again, this time, with a different group of athletes. >> one, two, three -- >> rockettes! celebrate what's new, the bigger, better menu at red lobster! with more of what you love! try our newest wood-grilled combination! maine lobster, extra jumbo shrimp,

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he tackled his way into the nfl hall of fame with both grace and fearlessness. tonight, our michael strahan is taking on yet another demanding physic physical challenge. he's not afraid, and his new line mates may surprise you, as

they stretch the star athlete in new ways. >> reporter: the radio city rockettes make it all look so easy. the kicks, the costume changes. that makeup. but how hard is it really to be a rockette all day? lucky me, the ladies invited me to find out. i'm here at radio city music hall, i'm so excited. you know why? because i'm about to become a rockette! >> arms pumping in there. >> reporter: first step? warming up. the rockettes are in up to four shows a day, kicking more than 300 times per performance. so, to prepare, they stretch. and they stretch. i don't know about this. and they stretch. there are perks to all the hard work. the rockettes say there's no need for a special rockette diet. they burn up to 1,000 calories each performance. >> put your right arm across. >> reporter: it was time for the dancing to begin. >> two, drop it three, hold four. we're going to go one, and

you're going to kick your right foot, together, jump, kick your left foot. and then you're going to do a big pose at the end. >> reporter: with the steps down. right, center, four times in the center. well, pretty much down. it was time to add some music. i'm so nervous now, because the music is going to be so fast. check this out. ♪ ♪ okay. i don't know what just happened. but -- one, two, three -- rockettes! a day with the rockettes, now that's what i call kicking the holidays into high gear. for "nightline," i'm michael strahan in new york.

>> michael strahan, renaissance man. i about tore a hamstring just watching him. thank you for watching abc news. tune into "good morning america" tomorrow, and as always, we're online at abcnews.com. good night, america.