"It's inappropriate because a lot of the 9/11 families who I know say, 'Look, I don't want that,'" O'Reilly said.
Behar countered, "This is America."
O'Reilly shot back, "Hold it, hold it -- listen to me, because you'll learn."
Boos erupted from "The View's" studio audience, and Behar called O'Reilly a pinhead while making a bunny-ears gesture behind his head. But O'Reilly plowed on, saying that "70 percent of Americans don't want that mosque down there."
When Behar asked, "Where's that poll?" O'Reilly didn't provide an answer. Instead, he offered a new reason for why he thinks that Park51 is inappropriate: "Because Muslims killed us on 9/11."
Goldberg spit out a phrase that was bleeped from the broadcast. Behar stood up and said, "I don't want to sit here. I don't." She walked off the stage, and Goldberg went with her.
"View" creator Walters tried to establish equilibrium after they left.
"I want to say something to all of you," she told the audience. "You have just seen what should not happen. We should be able to have discussions without washing our hands and screaming and walking offstage. I love my colleagues, but that should not have happened."
Then she turned to O'Reilly.
"Now let me just say to you, in a calmer voice, it was extremists. You cannot take a whole religion and demean them," Walters said.
O'Reilly offered an apology.
"If anyone felt that I was demeaning all Muslims, I apologize," he said.
A few minutes later, Behar and Goldberg returned to the set. Behar announced, "We're back. You apologized."
The incident drew a motherload of attention to "The View." On Thursday, the show's Web site averaged 10 times its normal traffic "which led to brief intermittent outages," according to a statement from "The View's" publicist.