Tonight, we are going to take you in an only-in-america faith-fuelled showdown. Two controversial figures and their respective fans faced off over creationism versus evolution. As you're about to see,... See More
Tonight, we are going to take you in an only-in-america faith-fuelled showdown. Two controversial figures and their respective fans faced off over creationism versus evolution. As you're about to see, it turned into a digital age spectacle. We've got to the creation museum in petersburg, Kentucky -- a lot of money went into this -- for a showdown of an age-old question. Where did we come from? This is Noah's arc. This place has been ridiculed as pseudoscience. This is a room where you see Adam and eve living alongside dinosaurs. A place where they try to prove that god created the Earth and all of its inhabitants in six days about 6,000 years ago. I say bring it on. I know I'm in the lion's den. Reporter: Own tonight, they're inviting in a devout nonbeliever. He's bill nye the science guy. Well loved for his 1990s pbs show for kids. He will debate ken ham, a former high school science teacher -- I beliedon't believe in evolution or millions of years. Who founded this $27 million, 70,000 square foot affront to modern scientists. Bill nye also has an agenda, to teach children not to believe in god. This whole thing came about because of this youtube video made by bill nye, criticizing the teaching of creationism to children. Denial of evolution is unique to the United States. It went viral. Reporter: And ken ham made a rebuttal video. Bill nye doesn't understand the word science. The word science means knowledge. Reporter: Ham challenged nye to come to the creation museum for a debate. And nye agreed. The story ricochetted around the internet and tickets sold out in just two minutes. Five days before the debate, bill nye is in his office at the planetary society in California, preparing the slides he'll show at the debate. I presume we will shake hands the way boxers do before they go at it and we'll go at it. I anticipate there will be no one in the audience who sees it my way. Later at his home, he shows us his bible. It's really an historical document. It's much more reasonable to me it was written by people, not an all knowing deity. Reporter: On the day of the debate, ken ham is in his office, prepping his own slides. We're just under four hours from the debate. Reporter: Haen his staff are abuzz. They're expecting a crowd of 900 with a million people watching online. The debate is now the top trending topic on Facebook. I think it's great. We're overcoming what I call a censorship out there in the culture to not let people hear the evidence against evolution. Some of the problems with evolution, the ed that cvidence that confirms creation. Reporter: Do you think you stand any chance of changing bill billnye's mind? God is the one that needs to change his mind. Reporter: As crowds pour in and go through metal detectors, that bill nye requested, ham says prayers. Lofty opinions raised against god. Bill nye is back up being made up. Do you get nervous for something like this? Absolutely. If you stop getting nervous, quit doing it. Reporter: Did you walk around this place? No. I've just seen pictures. Reporter: What do you think of dinosaurs living next to Adam and eve? On some level it's funny. Like the flintstones were funny. He arrives for the hand shake. Mr. Ham. Reporter: This is the first time you've ever met? Thank you for being here. Tails. Heads. And it is heads. I'll go first. Reporter: As we walked through the crowd, we realized quite quickly, it's not all creationists here. Not by a long shot. N nye fans or ken ham fans? Science fans. Bible fans. Bill nye. Reporter: How about you? Ken ham. Have you guys said a word to each other before? You have? Are you getting along? Do I need to get in there and break it up at all? No, we're good. Reporter: Backstage with only minutes to go, ham's nerves are starting to show. I'm just asking the lord to calm me down. So I'm not so nervous. Reporter: Game time. It's on. Ham's opening gamut is to attack nye's argument that believing in creationism means you can't be a good scientist by playing clips like this one of the man who invented the mri. I'm a young Earth creation scientists and believe that god created the world in six 24-hour days. Reporter: He goes on to argue when people's belief in the bible is eroded society crumbles. I love science. I want children to be caught the right foundation, that there's a god who created them, who loves them. Thank you very much. Mr. Ham, I learned something. Reporter: Nye starts out cordially enough but then takes a hard run at ham's assertion that god created the Earth 6,000 years ago and then flooded the whole planet 2,000 years later. There's a famous tree in Sweden, old tico is 9,550 years old. How could these trees be there if there was an enormous flood just 4,000 years ago? The Noah story comes in for particular scrutiny. Somehow Noah and his family were able to build a wooden ship that would house 14,000 individuals. And these people were unskilled. Reporter: Now the two men have a chance to take one another on directly. Why would you say Noah is unskilled? I didn't mean Noah. Neither did you. As far as Noah being an extraordinary ship right, it's very reasonable perhaps to you that Noah has superpowers. Reporter: Nye goes after a claim that scientists find particularly galling that dinosaurs and all other animals were vegetarians because the bible said so. I have not spent a lot of time with lions, but I can del they have teeth that raept really weren't set up for broccoli. Bears have teeth very much like a lion or tiger and yet most bears are primarily vegetarian. Reporter: Members of the audience were given a chance to submit questions in writing. How did the atoms that created the big bang get there. This is the great mystery. This is what makes us get up and go to work every day is to try to solve the mysteries of the universe. Bill, I just want to let you know there's a book out there that actually tells us where matter came from. And the very first sentence in that book says in the beginning god created the heavens and Earth. Reporter: After 2 1/2 hours, a standing ovation. If anyone was expecting a thorough comprehensive final dismantling, they would be disappointed. This debate will continue. Did Kim ham say anything that changed your mind in any way? Absolutely not. Reporter: Did bill nye change your mind on any level? No. Do you think you won? I thought it went very well. Reporter: Did you win? I never looked at it as winning and losing I'm going to passionately defend what I believe. We're more alike than we are different. We're all descended from Adam and eve. That's why. Reporter: Are we witnessing the birth of a friendship here? We're witnessing the continuation of mutual respect for colleagues that have passionately held beliefs. That's a great way of putting it. That's good. Reporter: Fair enough. Reporte as the crowds head out into this ice storm on this planet we all share, even if we don't agree on its origins, this hopeful notion, nearly 1,000 people just came together to debate one of the most sensitive questions around, and it was entirely civil.
This transcript has been automatically generated and may not be 100% accurate.