tonight on "nightline," portrait of a meltdown. in an abc news exclusive, bree olson, one of charlie sheen's so-called goddesses, talks about why she left him and what life in charlie's mansion was really like. >> it was like you could cut the air with a knife. jaws. after two shark attacks on the east coast in the last month alone. we go underwater with scientists seeking to understand these fearsome creatures. nick watt gets up close, maybe too close, to the great white. and, spaced out. as the final space shuttle flight glides into history. >> main gear touchdown. >> we look to the sky to see how far we've come and how far we have to go.

>> announcer: from the global resources of abc news, with terry moran, cynthia mcfadden and bill weir in new york city, this is "nightline," july 21st, 2011. >> good evening, i'm b bl weir. through countless interviews, a web cast and national tour, charlie sheen seemed to provide most of the western world with a front row seat to his epic meltdown this spring. but that was his version. tonight, we hear from a woman who was really in the room. a farm girl and pre-med student turned porn star and goddess of the sheen estate. after leaving the scorned sitcom star, she decided to tell her version of events, and does just that with abc's dan harris. >> reporter: she was one of the star players in charlie sheen's alternate universe. >> these are my girlfriends. the women that i love, that have completed the three parts of my heart. >> reporter: and now, bree olson is lifting the curtain for the

first time, revealing this situation to be even stranger than we already thought. so, how did a farm girl from indiana end up in the middle of this bizarre love try angle? well, first, it helps to be a believer in polygamy. what do you find attractive about polygamy? >> i just think it's a more natural way of life. and i believe as we were evolutionizing, there were more, you know, men that were in control of several women. >> reporter: olson's road to meeting charlie sheen began when she was a 19-year-old pre-med student named rachel oberlynn who one day decided to do a online search for porn jobs. what got you interested in the adult movie business? >> it's something i always had been interested in. i've always been very insatiable sexually. >> five years later, she was one of the most popular women in porn.

a friend introduced her to sheen. what did you like about him? >> he made me laugh, just every other thing he said. he doesn't have a regular, how's the weather conversation, you know? >> reporter: she says she was aware of reports of his violence, allegedly holding up a knife to brooke mueller and trashing a hotel room with another porn star in it. but she says she figured it was all tabloid misrepresentation. have you seen him behave in a violent way? >> no, i've never seen chahaie believe violent in any situation. >> reporter: she also swears up and down that she's never seen sheen do drugs, even when she moved into his home in february. what did surprise her, then, she says, is finding another woman there, natalie kenly. a model who once graced the cover of a marijuana magazine. so, you moved in and you find out there's another woman living there, too? >> on the ride over there, his assistant rick says, did charlie

th tell you about natty? i was like, who? and i got to the house, and there she is, standing in the kitchen. and she did not look too happy to see me there. >> reporter: was it a tense environment then in the home? >> at times. you could cut the air with a knife sometimes. i felt like i couldn't show charlie the affection and the love that i wanted to show him because of how she would react. >> it's unconvenenonal and seems crazy y everybody else, but for us, i mean, it works well. >> reporter: she said on television that everything was great. >> yeah. well -- i don't know what to tell you. i think she was trying to convince herself that it was great. but she was crying, like, every day. she was really upset about it. >> reporter: one week after olson moved in, the war between sheen and the creator of "two and a half men" began. and during all of those interviews with all that talk of tiger blood, warlock brain and

bi-winning. >> i am on a drug, it's called charlie sheen. >> reporter: olson and natty watched smilingly from the couch. a lot of people saw those interviews that he did and thought, this guy appears to be psychologically unbalanced. >> now it's a polygamy story, i mean, come on. >> he was just cracking so many jokes. he was relaxed and trying to have fun and people that don't know him, they just don't get it. >> reporter: but even during those incomprehensible web casts -- >> i pluck them or suck them from the heart of my brain. >> maybe that was his way of venting or getting stress out. stress release. because i was with him almost every time of the day and he seemed perfectly kosher and fine to me. >> reporter: she says the memory that stings the most from that period was the uproar over the goddesses caring for sheen's two young sons. >> that is so absurd that, oh, a porn star is not capable of being around children.

just because i've chosen to do what everyone else does in this whole entire world on camera does not make me ineligible to be around children. >> reporter: olson insists sheen was a great father and was devastated that night when the children were finally taken away. the boys are currently in the custody of their mother, sheen's ex-wife brooke mueller, though mueller has admitted to having drug problems of her own. olson stayed with sheen through the beginning of his tour, but then, she says, the pressures of e road and the meddling of natty led her to leave. these days, she's on the cover of "playboy." but though she's single now, you will not catch her saying anything negative about charlie sheen. you are pretty fiercely protective of him. >> i always will be. i see little charlie in him, you know? i see, like, little boy charlie that i just want to protect from, like, the world that goes after him. >> reporter: she denies that her

relentless positivity wie tity doesn't have anything to do with her desire to cross over to main stream acting. >> i think that i'm a damn good actress and i think that i could be in blockbuster hits. i think i could be a main character on a series role. >> reporter: she's going to give it a year, she says, and if it fails, she plans to get married, to just one man, and have children. for "nightline," this is dan harris in new york city. >> our thanks to dan for that. and with shark attacks back in the news, our cameras go in for a closeup of nature's most efficient killing machine. comes centrum.

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>> announcer: "nightline" continues from new york city with bill weir. >> the most recent victim was only 6 years old, playing in bathtub deep water when the shark grabbed her leg. that was yesterday on the north carolina coast. she's in good condition tonight, but both movies and expepes teach us shark activity picks up near beaches in the summertime. ironically, great whites, the king of the species, are now in need of protection from us, not the other way around. abc's nick watt is here now with an encore presentation for our series "into the wild." >> repororr: the beach is all about swimming, searching, pad. ing, playing. but we've all seen "johns." we all remember that music. and in the back of every beach goers mind lurks the fear of the fin. somewhere out there, the great white. we've come to meet one of the most feared, demonized and

endangered predators on earth face to face. >> nick? good luck. >> reporter: this is arguably the most shark infested water on earth. >> how's the water, nick? >> reporter: cold! and now, we're in it. visibility is bad. we know the great whites are here, but we can't see them. blood and guts will entice passing sharks. a tuna head will draw them headlong at ourr cage. but where are they? i'm flinching at shad domes, disoriented and shared. and then, suddenly -- this prehistoric predator is 15 feet of lean, mean, killing machine. hundreds o o teeth and an insafable appetite. his fin was, like, that far away. you could see his gills -- oh. if i was brave -- after a few

anxious minutes, he's back. and great t ites have an attack speed of 45 feet a second. hang on. why are we doing this? well, because the great white is in trouble. sharks are older than the dinosaurs, but now, the king of the ocean is in danger of extinction. >> as soon as i became a diver, my first encounter with a shark was just enough to pull me into the world of sharks from there on . >> reporter: julie anderson is a new york based conservationist. allison cox, a marine biologist. they call themselves the shark angels. today, a research trip off the coast of cape town. out on the water, we saw a pod of playable dolphins and an adorable 2-yeararld whale. great whites are a much tougher sell. >> it's not like whales or dolphins where people want to care about them. 100 million sharks are killed a year. a lot of people don't know that.

when they do know that, they say, so what? why should i care? >> reporter: why should we care, particularly about the man-eating great white? >> white sharks are apex predators. and predators are essential to the health of an ecosystem. >> reporter: cage diving does have its critics who believe feeding wild animals upsets nature. a price worth paying if it teaches us to care? the great white population has dropped 70% in 50 years. they are huntete for their jaws teeth and fins. and many drown in nets designed to keep swimmers and surfers safe. in wintertime, great whites george themselves here at sale island, but where do they go in summer? now we know. they go to the beach, like the rest of us. so, at the time of year that we're swimming, the sharks are hunting in shallow water. here in cape town, there are no nets, just shark spotters on the cliff who sound a warning.

this scares me to death, but for allison, proves that sharks and man can share the ocean. >> there's been over 400 shark sitings in the last three years and no negative interaction, attacks by sharks at the beaches. >> reporter: and, she says, sharks don't want to eat humans. the shark angels dive uncaged with sharks, though admittedly, not great whites, to prove their point. >> most of the time, they don't actually eat the person and it's a bite and release. bebelieve that's mostly investigation. they simply don't know what we are. >> reporter: can't say the shark angels have made me feel a whole lot safer. >> love them or hate them. obviously, i have a passion. we need sharks on this planet. >> reporter: back in the cage, i'm still trying to decide whether i do want to share my planet with this. enough is enough.

me and the producer, a ball of nervous energy. i was almost lost for words. i don't any i ever want to do that again. i could see the shark's eye about this far away from me. and his mouth was open. teeth were bared, trying to grab the bit of chum. yeah. this has made me more scared of sharks -- probably. i still hate great whites. but now, i do admire them. from this close, it hard not to. they survived 20 million years in our oceans. now, our grudging respect might be all that saves them from extinction. i'm nick watt for "nightline" in south africa. vegas! now?! [ female announcer ] two hours to vegas. two hours to whiten. ♪

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to some, it was one of the most glorious machines ever built. and a symbol of america's unique ability to slip the surly bonds of earth whenever we wanted. to others, it was a $200 billion space truck running zero gravity errands. either way, the final space shuttle mission landed today. and for abc's john nvan, that is a monumental "sign of the times." >> landing gear down and locked. >> reporter: when the shuttle touched back down this morning, there were no crowds, no marching bands. and, in the pre-sunrise, it felt almost as if they turned out the lights already. >> launch of america's first space shuttle. >> reporter: and while america's space program over half a century marked us, handling us heroes, delivering triumph and disaster, littering our language

with terms like t-minus and a-okay and go for liftoff and even, "houston, we've got a problem," -- >> the final liftoff. >> reporter: the liftoff on july 8th was it. as the clouds above cape canaveral closed around t ts 135th and final launch of the space shuttle, it was the end f america doing what it has done for more than 50 years. and that is human space exploration. man in orbit. man on the moon. man driving around on the moon. woman in orbit inside the shuttle. man in orbit outside the shuttle. it has been a long, dramatic ride. and for a time, at least, it was one that we were willing, most of us, to pay for. and some of us had to pay with our lives. america's astronaut program lost 21 men and women, either on missions or in training from missions. and though there was compensation in the early days in the form of public adoration,

the pay itself was never very good, nor were the hours, nor, very often, the working conditions, dh were cramped, at best. but then, these people got to be apart of history. they also got the spectacular views out the window. and, a sensation unmatchable of the kind that astronaut andy thomas told "nightline" about a few years ago, ahead of what would be his fourth trip. >> you start this teeth chattering ride, just vibrations, massive vibration, shaking, shaking, shaking. you have the window, you can see the launch tower just fall to the side as you climb upwards. if there's any clouds, they just rush by the window. you can see the horizon spin around. >> reporter: a view that no one will be seeing from a u.s. spacecraft again for quite awhile. for a time, president bush still kept alive the notion of getting to the moon. >> we will undertake extended human missions to the moon. >> reporter: president obama nixed that but said things about going farther.

>> we've set a goal to, let's ultimately get to mars. >> reporter: but everyone noahs now that the commitment to space exploration by humans -- >> that's one small step for man. >> reporter: that got us to the moon in the middle of the last century, it just isn't there in this century. it's odd to think it's been four decades since a human walked up there, and that we c cld make it there then. and now, really, we can't. so, for the short-term, at least, u.s. astronauts may have to hitch rides on other nation's rockets and u.s. exploration will have to continue to rely on robots. already, all of that, the heroics, the distant journeys, the images l le this one of the shuttle reentering the atmosphere only this morning, it's already feeling like something that happened once upon a time. i'm john donvan for "nightline" in washington. >> and wherever we head next, we'll be there to cover it for you. thank you for watching abc news.