Holocaust denial, or the belief or assertion the Holocaust did not happen or was greatly exaggerated, is perhaps the most prominent antisemitic conspiracy theory out there.
The event, which was the genocide of European Jews during World War II, cost 6 million lives, not including the lives of millions of others, including ethnic Poles, the Roma, the disabled and gay men, who were persecuted under the Nazi regime.
There is no doubt the Holocaust took place, so what would an "opposing view" of it entail?
That's what's mired the Carroll Independent School District in Southlake, Texas, in controversy this past week, after a top administrator advised teachers to present "opposing" viewpoints if they're going to assign books about the Holocaust.
Gina Peddy, the Carroll school district's executive director of curriculum and instruction, made the remarks during a training session on which books teachers can have in classroom libraries.
A Carroll staff member secretly recorded the training and shared the audio with NBC News.
Referring to a new Texas law that requires teachers to offer multiple perspectives when covering "controversial" issues, Peddy said:
"Just try to remember the concepts of [House Bill] 3979."
"And make sure that if you have a book on the Holocaust, that you have one that has an opposing, that has other perspectives."
When asked by a teacher how one can "oppose" the Holocaust, Peddy responded:
"Believe me, that's come up."
The recording soon went viral, generating significant outrage online.
Peddy has not responded to requests for comment.
However, Carroll spokeswoman Karen Fitzgerald said the district "recognizes that all Texas teachers are in a precarious position with the latest legal requirements" in regard to the law, noting that an updated version will go into effect in December:
"Our purpose is to support our teachers in ensuring they have all of the professional development, resources and materials needed."
"Our district has not and will not mandate books be removed nor will we mandate that classroom libraries be unavailable."
According to Clay Robison, a spokesman for the Texas State Teachers Association, there is nothing in House Bill 3979 that explicitly mentions classroom libraries.
He issued a statement criticizing Peddy's remarks:
"We find it reprehensible for an educator to require a Holocaust denier to get equal treatment with the facts of history."
"That's absurd. It's worse than absurd. And this law does not require it."
The Carroll Independent School District also found itself in the news earlier this month after board trustees voted 3-2 to reprimand a teacher who had assigned an anti-racism book to her class.
The book, This Book is Anti-Racist: 20 Lessons on How to Wake Up, Take Action, and Do the Work by Tiffany Jewell, was at the center of a complaint filed by parents who voiced their opposition after their child brought a copy home from school.