♪ this is not a drive-by by by ♪ just a shy guy looking for a good time ♪ this is "nightline." >> tonight, his final hours. new details emerging amidst an outpouring of grief for robin williams. the actor that made us laugh with "mrs. doubtfire." and made us cry with "what dreams may come." the latest insights on robin's final moments, as famous friends remember a comedy icon. plus, robin's struggles. the money woes. the battle with addiction. and the darkness behind the laughter of a legend. >> joking about it is a coping mechanism. >> what we now learned about robin williams' most difficult hours. and swimming with sharks. they're massive. toothy and 25 feet under water.

we're on their home turf. >> holy cow. >> our team brings you up close. maybe a little too close. >> i want to go back in. >> the fiercest stars of shark week. >> that's crazy. but first, the "nightline 5." >> you're invited to the jcpenney friends and family event. save with 25% of coupons on all of the things you love. bring your friends and family to the extra 25% event. heart burn alert. nexium can take 24 hours to work. zantac's difference. zantac rushes relief in as little as 30 minutes. for relief without the wait. try zantac.

good evening. and thanks for joining us. the shock wave surrounding the tragic death of robin williams continues to reverberate as new details paint a heartbreaking picture about the dark side of the actor who brought so much joy to so many fans. on screen, his performances were explosive, energetic and wildly inventive. but robin williams' brilliance in front of the camera concealed a private sadness. tonight, the last moments of a legend. it's "the life and death of robin williams." >> i miss him. and i'm sure you guys do, too. what a gift he was to all of us. >> it's just shocking how fragile life is. >> i was a kid when it was the first time i saw an actual human being be as funny as bugs bunny. >> reporter: as hollywood mourns the death of one of its brightest stars, new details confirming the sad truth about how williams died.

>> the preliminary results of the forensic examination revealed supporting physical signs that mr. williams' life ended from asphyxia due to hanging. >> reporter: the actor apparently hung himself with a belt. but that wasn't all they found. >> the inside of mr. williams left wrist had several acute, superficial transverse cuts. a pocket knife was located in close proximity to mr. williams. >> reporter: his wife told police she last saw her husband about 10:30 sunday night. but the couple slept in separate beds. >> mr. williams was last seen by his wife at approximately 10:30 august 10th, when she retired for the evening in a room in the home. >> reporter: when she woke up the next morning, she didn't see him. >> at approximately 10:30 a.m., on august 11th, 2014, mr. williams' life left the home, believing mr. williams to still be asleep. >> reporter: just before noon, after williams failed to answer the door, his assistant grew

concerned. >> at that time, the personal assistant was able to gain access to mr. williams' bedroom. and entered the bedroom to find mr. williams, clothed, in a seated position, unresponsive. >> reporter: and called 911. >> apparent suicide, attempt from hanging. >> police respond? >> affirmed. >> reporter: had williams been drinking that night? after his repeated struggles with alcohol? we won't know for a few weeks. but at today's press conference, the discussion of a note raised eyebr eyebrows. >> we're not discussing a note as the investigation is ongoing. and that will be discussed at a future time. >> reporter: williams was battling severe depression. as many as one in every ten americans suffer from depression. >> the reason we misunderstand depression so much is that you can't show me depression on an x ray. you can't show me a court of depression. >> reporter: to the outside world, williams was the

hilarious -- >> ladies, how about this? instead of breast implants, speakers. wouldn't that be cool? >> reporter: larger than life. >> is this fun? >> reporter: and wholly original comedian. >> we're going to play lizzie borden. >> reporter: who made others laugh. his depression and substance abuse was something he struggled with for years. he checked into rehab most recently last month. >> this is what we call a dual diagnosis scenario. you have someone dealing with the struggles of addiction through the years. and you put depression on top of that. and the interaction between the two is multiplicative. >> i'm on my way to dublin. >> reporter: he was brutally honest about his fight for sobriety. in his sandup routine. >> you will violate your standards quicker than you can lower them. >> reporter: and in candid interviews, like this one with diane sawyer, in 2006, after he got out of a stint in rehab. >> was there one moment you fell

into it again? was it one day? >> it's usually very gradual. you're standing at a precipice. and you lock down. and there's a little voice that says, jump. just one. there's a voice that goes, jump. and the idea of just one. >> how hard was it to talk to your kids? your wife? >> it's hard admitting. once you've done that, it's easy. the sad thing is, you think that people don't notice. and you find out later on, we knew. >> reporter: williams had open-heart surgery to replace his aortic valve. a surgery that some have linked to depression. >> it is a risk factor that is looked at, postsurgically. you want to pay attention to folks that they're unable to engage the world. it kind of visits your mortality. >> reporter: williams discussed his own mortality with our barbara walters less than two

years after his surgery. >> you said that the surgery was humbling. >> totally. this is the big one. this is the one where they're dealing with the ticker, the main. the only other one more invasive is brain surgery. >> reporter: it wasn't just health issues. williams had stress in his personal life. he was device divorced. and was honest about the financial pain it caused. telling "parade" magazine, divorce is expensive. i used to joke they were going to call it all the money. but they changed it to alimony. it's ripping your heart out through your wallet. in that same interview, he said he was downsizing his life. and could no longer afford his 650-acre weekend estate in california's napa valley. he listed the villa of smiles for nearly $30 million, shortly before he died. the 20,000-square-foot 5-bedroom estate, features a home theater, tennis courts and beautiful views of the napa valley. and the home is still on the

market. his professional life may have proved stressful, as well. last year, he returned to tv once again for a cbs show called "the crazy one." telling "parade" magazine, the idea of having a steady job is appealing. but the show was canceled this past may, after just one season, due to poor ratings. >> the immense jimmy. >> reporter: robin williams spent his final days in marin county, just outside san francisco, where the huge star was a seemingly regular guy. >> nice to all of the neighbors. really appreciated his kindness. >> i loved his sense of humor. i loved his -- the spontaneity of his life. >> reporter: an avid cyclist, williams had 100 bikes in his collection. >> he loved cycling. >> reporter: he took them to this repair shop. the owner, tony tom, was williams' close friend and biking partner. >> i'll miss him. >> reporter: tony said biking

gave williams some peace and tranquility. >> he came shortly after tom belushi passed away from overdose. and he said cycling saved my life. and he says, biking is a whole lot better for you than cocaine. >> mr. williams? >> reporter: but the legendary comedian and movie star was also known for championing the underdogs. >> oh, look. it's showtime. >> reporter: using his star power to bring attention to issues like homelessness, in movies like "the fisher king." >> one more thing, never take your eye off the ball. >> reporter: even testifying on capitol hill about the issue. >> i've seen firsthand how homelessness affects children. >> reporter: and his lasting work with the uso, lifting the spirits of 90,000 servicemen and women stationed overseas. >> when i come here, for you. >> reporter: and across the country, landmarks that williams made famous over the course of his storied career, are now

memorials. that bench in boston, from "good will hunting." now surrounded by tributes in chalk. that movie launched the careers of two unknowns, ben affleck and matt damon. and earned all three oscars. he made matt and my dreams come true. what do you owe a guy that does that? judging from the tributes of fans from all over the world, almost everyone felt they owed a lot to robin williams. >> you don't know about real loss. that only occurs when you love something more than you love yourself. >> reporter: in the end, perhaps williams loved making his fans happy, more than he loved himself. but his loss is ours, as well. >> an epic talent. a lasting legacy. up next for us, the scariest creatures to ever star on tv. we bring you eye-to-eye with the sharks of shark week. [ terri ] my antidepressant worked hard to help with my depression.

but sometimes, i still struggled to get going, even get through the day. so i was honest with my doctor. i told him i'd been feeling stuck for a long time. he said that for some people, an antidepressant alone only helps so much and suggested we add abilify (aripiprazole). he said that by taking both, some people had symptom improvement as early as 1 to 2 weeks. i wish i'd talked to my doctor sooner. [ female announcer ] abilify is not for everyone. call your doctor if your depression worsens or you have unusual changes in behavior, or thoughts of suicide. antidepressants can increase these in children, teens and young adults. elderly dementia patients taking abilify have an increased risk of death or stroke. call your doctor if you have high fever, stiff muscles and confusion to address a possible life-threatening condition. or if you have uncontrollable muscle movements, as these could become permanent. high blood sugar has been reported with abilify and medicines like it and in extreme cases can lead to coma or death. other risks include increased cholesterol, weight gain, decreases in white blood cells, which can be serious, dizziness on standing, seizures, trouble swallowing and impaired judgment or motor skills.

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okay. whether they thrill or terrify you, shark week, is reeling in a record-breaking 4 million viewers. but for some shark enthusiasts, the couch is not a close enough encounter. some like "good morning america's" ginger zee, dive in with no cage, no protective gear, to go nose-to-nose with the ocean's most feared predator. >> reporter: they are one of nature's most-feared predators. and that is me, getting up close and personal. holy cow.

>> this is so gnarly. >> reporter: it's really the only way to do discovery channel's shark week. before we get to that adventure that finds me 25 feet down, surrounded by dozens of sharks, let's set the record straight. sharks don't want to eat humans. they want fish. still, reports of attacks are on the rise. last year, there were 72 unprovoked attacks worldwide. ten of them, fatal. >> 911, what is your emergency? >> i got a shark bite. >> earlier this summer, a woman tubing with her friends in ft. lauderdale, florida, was bitten by a bull shark. some of her wounds too gruesome to show. >> i get hit by something. >> get out of the water. >> reporter: and just last month, an eight-foot great white shark bit a swimmer off a california beach. >> i was staring at the shark, eyeball-to-eyeball. >> reporter: scientists say

attacks are on the rise because more sharks are coming to the coast. and more humans are going in the water. and sometimes, sharks confuse humans with food. why, oh, why, would i be jumping in? no stage, no chain mail suit. the reason, to learn firsthand, as scary as they look, we are much more dangerous to them than they are to us. for every one human killed by a shark, 20 million sharks are killed by humans. my adventure begins in old bahama bay. here we are. the beautiful bahamas. discovery invited me to meet of their shark week secret weapons. stuart cope. a legend in the bahamas for his intimate challenge of the beasts of the deep. >> they'll come up and taste before they bite. as long as you don't let them taste you, you're in good shape. they want to eat what they're supposed to eat, which is fish. >> and we had plenty of fish to get them interested. that would be a bunch of chum or

fish guts in an icicle. among the species we're going to see, tiger sharks. ranking third in the world for unprovoked attacks on humans. and the tigers are the biggest. >> they're very large. >> reporter: how long? >> they're three femeters, four meters long. >> reporter: 25 miles offshore, our destination, tiger beach. 45 minutes later we arrive. and we're not alone. they're here, everybody. and so are we. and soon, i'd be in there with them. those sharks on the surface are called lemon sharks. >> these are small compared to the tigers. they're still very large sharks. >> reporter: i thought the small ones would be small. the tigers lurking below, are 9 to 18 feet long, weighing more than 3,000 pounds. he knows all about shark attacks and shark preservation. >> not too long ago, my nephew

got bit by a shark. there's been a rise in shark attacks in hawaii. and my pursuit was to find out why. >> reporter: still, the odds of being attacked by a shark are only 1 in 11.5 million. but what are the odds of being attacked if you dive into a feeding frenzy of sharks because a cage, just wearing a wetsuit? to help the sharks distinguish between humans and food, we have to keep our flippers on. and our wetsuit zipped tight. before i knew it, we were in that turquoise water. they're so close. surrounded. it's pretty down here. i feel like i'm in a movie. so surreal. and the sharks, eerily curious, weren't coming after us. >> they're not interested in us. >> reporter: they didn't mind as

we petted them. oh. and remember that chumcicle? now, they're all over it. setting off full-on chaos. >> oh, my god. the shark has the camera in its mouth. it's so gnarly. oh, my god. >> reporter: the most amazing moment, watching the shark experts caress the tiger sharks, almost like a dog getting its belly rubbed. what's he doing to him? he's coming in for a cuddle. >> we're coming up. >> reporter: up and out of one of the most enlightening trips i have ever had. oh, my god. wow. back on the boat, none of us could believe what we saw. >> oh, my god. >> [ bleep ] gnarly. >> that was the heaviest thing i've ever seen. heavier than my kids popping up. i'm telling you, man. that was crazy. >> reporter: even an old pro, like stuart, was shocked.

>> that was one of the best dives i've ever been on. >> reporter: and despite what happened to others who have been attacked by sharks, most experiences with these animals are like mine, incredible and humbling. for "nightline," i'm ginger zee, in the bahamas. >> shark week is airing on the discovery channel this week. just ahead for us, news, tonight, as hollywood loses another bright star. we bid farewell to actress, lauren bacall. >> you know how to whistle, don't you, steve? you just put your lips together and blow. huh, fifteen minutes could save you fifteen percent or more on car insurance. everybody knows that. well, did you know the great wall of china wasn't always so great? hmmm...what should we do?

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it's been a sad week for hollywood. first, the loss of a comic legend, robin williams. and now, news that another legend from hollywood's golden era, actress lauren bacall, has passed away at the age of 89. tonight, we pay tribute to one of the silver screen's original sirens. lauren bacall had the look, that sultry, sideways glance and that throaty voice full of promise. >> you know how to whistle, don't you, steve? you just put your lips together and blow. >> reporter: bacall's life story is the stuff that hollywood dreams are made of. spotted at 19, she was brought to hollywood to star in her first picture, opposite humphrey bogart, in "to have and have not." >> what's the decision? >> i don't know yet. >> reporter: they fell in love. and despite a 25-year age difference, married the next year. on and off screen, they were

hollywood's golden couple. >> i like that. i'd like more. >> reporter: in 1957, bogey died of cancer. bacall had a well-publicized romance with frank sinatra. and an ill-fated marriage to actor jason robards. >> every one of them was a mistake. >> reporter: she matured on screen, from seductress to the elegant older woman. >> there was a man in my compartment last night. it was pitch-dark and my eyes were closed in terror. >> the mother's dating. and the daughter stays home alone? >> mom, who is looking? >> reporter: people did look. bacall commanded attention. she exuded class, elegance, independence. in her 70s, she was nominated for an oscar, and honored at the kennedy center. late tonight, bacall's son thanked supporters via facebook.

saying, thanks to every one of my friends for all your good wishes. it's hard to believe, she once said, that it all happened to me. >> of course, you do have a sense that it's quite -- how could i have lived through all of that? >> reporter: a life well lived, now over, at age 89. and hollywood mourns again tonight. thanks for watching abc news. tune into "good morning america" tomorrow. and as always, we're online at abcnews.com. good night, america.