THE GUINNESS WORLD RECORDS PHENOMENON: THE STORIES BEHIND SOME OF THE MOST UNBELIEVABLE RECORDS, ON ABC NEWS' "20/20"

A man who sat in a bathtub with 87 rattlesnakes... A woman with nails 33 inches long... A man who did somersaults for 10 1/2 straight hours... A man who stands 8 feet 5 inches tall... What do all of these people have in common? They are all Guinness World Record holders. For the last 53 years, the Guinness World Records book has recorded feats and oddities from the ridiculous to the sublime. Matched only by the Bible for popularity, the book attracts people from every country in the world who are attempting to set Guinness World Records. Who are these people and what motivates them? "20/20" reports on amazing stories behind some of the unbelievable records, FRIDAY, NOVEMBER 23 (10:02-11:00 p.m., ET) on the ABC Television Network. Reports include:

* The Phenomenon of Guinness World Records: Every year officials at Guinness World Records receive some 50,000 applications from ordinary people vying for a spot in the book. For some, it's risking life and limb. Jackie Bibby is the Guinness World Record holder for "Sharing a Bathtub with the Most Rattlesnakes." On November 5, Bibby bested his own record of 75 by a dozen snakes, bringing the number to 87. He works exclusively with Western Diamondback rattlesnakes which have a potentially fatal bite. "I like pushing the envelope," said Bibby. "I'm a thrill seeker and, you know, there are those [of us] that are adrenaline junkies." Deborah Roberts reports.

* Guinness World Records By Birth: At nearly 7 feet, 9 inches tall, it comes as no surprise that Bao Xishun draws attention everywhere he goes. A sheep herder from Inner Mongolia, Bao held the Guinness World Records title of the Tallest Man in the 2006 and 2007 books. But Bao was in for a surprise this year, and so was 36-year-old Leonid Stadnik of Podoliantski, Ukraine, who is 8 inches taller than Bao. No one had ever heard of Stadnik before he was announced as the 2008 record holder in the tallest man category. "20/20" traveled halfway around the world to see Stadnik and find out what things look like from his point of view. David Muir reports.

* Guinness World Records By Choice: "20/20" looks at two record holders who have chosen to manipulate their physical appearances to comic-book proportions. Guinness World Records are about extremes, and that's certainly the case for the women who hold the records for the smallest waist and the longest fingernails. Cathie Jung, a 70-year-old grandmother from North Carolina, has a 15-inch waist -- that's narrower than a family-size mayonnaise jar. And Lee Redmond, a 66-year-old great grandmother from Utah, has 33-inch fingernails. Both women have been working on their unusual body modifications for over 20 years. Jay Schadler reports.

* Guinness World Records Is My Life: Holding a world record requires dedication, and no one knows that better than the person who holds the most records in the world. As a young boy flipping through the pages of the Guinness World Records, Ashrita Furman never imagined he would one day be featured alongside his childhood idols. He says achieving a Guinness World Record was just a dream. "There was no possibility as far as I saw it," Furman says. "Because the records that really impressed me were physical records, and I knew there was no way I could do it." But today Furman currently holds 69 records. David Muir reports.

* Guinness World Records Groups: What if you've always wanted to get into the Guinness World Records, but you're not willing to let your beard grow past your knees, or the thought of eating 50 hot dogs in one sitting gives you the shakes? Here's another idea: gather up all your friends and family and all their friends and families and so on and so on, because group records are a huge part of today's book. How about the record for the largest gathering of people with the same last name? The most champagne bottles being uncorked at the same time? Or the most bikini-clad women gathered for a single photo shoot? These are but a few of the group records thousands of people have attempted in the past year. Bob Brown reports.

"20/20" is anchored by Elizabeth Vargas and John Stossel. David Sloan is executive producer.