When the AMC Network announced in March of 2010 that it was greenlighting a new six-episode zombie series spearheaded by three-time Academy Award-nominee Frank Darabont, many in the industry thought it a giant risk. Would people tune into a gore-filled post-apocalyptic undead thriller based on a comic book? It took only one or two episodes of season one to see that the popular answer was yes. A little over two and a half years later, AMC's gamble is now a ratings juggernaut, second only to Sunday Night Football

"Thank you to the fans for making 'The Walking Dead' such a tremendous success," the network said after season three premiered with more than 10.9 million viewers tuning in. "We are honored and humbled that television's largest adult audience resides on AMC."

Interestingly enough, AMC was not the first choice for "Walking Dead" producer Gale Anne Hurd. The 56-year-old and former wife of film director James Cameron, actually approached both NBC and HBO to pick up the series. But in an odd twist, more so for the latter, both passed because of show's violent drama.

Greg Nicotero, makeup effects artist and co-executive producer for "The Walking Dead" praises Hurd in a new interview with the Huffington Post for refusing to deviate from the original tone. 

"When NBC and HBO both said that they'd be willing to commit to a The Walking Dead television series if the production team significantly toned down the graphic novels' violence and gore, Gale said, 'No, thank you,' and then began shopping the show around to other networks," Nicotero told the site. 

"Thank goodness we wound up at AMC. They totally get this show. Right from the beginning, they've been completely trusting and supportive of what we've been trying to do with this series," he added. 

It's amazing to me that HBO, known for such violent series as "Boardwalk Empire" and "The Sopranos" would take issue with the killing of zombies. But their loss was certainly AMC's gain - and, according to Nicotero, likely resulted in a much better series. 

"We spent a million and a half on that prison set. And all the months that that took to build, AMC never once checked up on us," he said. "They never flew an executive or an accountant out to Georgia to make sure that we were spending that money the way that we said we would. Now that's trust."

"The Walking Dead" on AMC airs Sunday at 9PM E/T. 

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Why HBO passed on 'The Walking Dead'
The post-apocalyptic drama, which pits humanity against a zombie virus, was deemed too violent by execs at HBO and NBC.