Poster showing 'Arbeit Macht Frei' sign pulled from big-box stores in the US. But why was it being sold at all?

Walmart and other big-box discount stores in the US are known for their ubiquity and variety; wherever the shopper goes, there he shall find everything he needs or wants.

But several popular retailers became the center of a new controversy on Monday, after being forced to recall "decorative posters" labelled with the phrase "Arbeit Macht Frei," German for "work sets you free" - the slogan notoriously on the sign for the Auschwitz-Birkenau death camp during the Holocaust.

The phrase somehow slipped past the notice of several popular stores in the US, according to ABC News, including Walmart, Sears, and Amazon.com.

Several rushed to recall the item.

“We were horrified to see that this item was on our site. We sincerely apologize, and worked quickly to remove it," a statement from Walmart read. "The item was sold through a third-party seller on our marketplace. We have shared our disappointment with them and have learned they are removing the publisher of this item entirely from inventory.”

Sears also pulled the poster from its website. "The item, which was listed by an independent third-party on Sears Marketplace, violates our guidelines and was immediately removed," a statement said.

Sears's own listing had a number of issues, DigiDay reported. The original description there initially listed the location as Dachau, not Auschwitz. In a sinister twist, one alert Twitter user even tweeted a screenshot of the description while it was still up, noting that the "similar items category" featured - of all things - ovens.

Sears quickly backpedaled on the move, which they alleged was unintentional.

“Regarding the placement of the Sears products at the bottom of the Web page, those are special sale items that currently appear on millions of product pages," it claimed. "While clearly unintentional, we sincerely apologize for the proximity of the positioning.”

Amazon.com did not respond to ABC's requests for comment.