Thieves today stole the notorious metal sign hanging over the entrance of the former Nazi death camp of Auschwitz that reads "Arbeit macht frei" (Work makes free), officials said.
Some 1.5 million people, mostly Jews, perished in the Nazi death camp located in southern Poland during the second World War. Prisoners arriving at the camp used to enter via a relatively small iron gate topped by the German-language motto.
More than 200 hectares of the former death camp became a museum after the war ended.
"Early this morning the guards patrolling the site noticed the sign was not in its place," Jaroslaw Mensfelt, the museum's spokesman, said. "We immediately notified the police."
Mr Mensfelt said there were numerous cameras installed at the site and said local police were now analysing the film. He said no further details regarding the theft were available.
"We have already installed a replica sign over the gate. It has been used in the past when the original was being repaired. I hope the original will quickly be retrieved and the thieves caught," Mr Mensfelt said.
"This is not only a theft but a horrible profanation in a place where more than a million people were murdered, in the biggest such site in this part of the world. This really is a disgraceful act."
The wording of the sign became a symbol of the Nazis' efforts to deceive their victims into a false sense of security before murdering them.
Some Jews and other groups arriving at the camp would have thought they were coming to do forced labour, not to be killed as part of a deliberate systematic policy of genocide.
Hundreds of thousands of people visit the museum every year, but ticket sales are not enough to maintain the open-air site with its 155 buildings, including the gas chambers, 300 ruined facilities and hundreds of thousands of personal items.
Auschwitz prisoners died of diseases, sub-zero temperatures, starvation and in medical experiments as well as being gassed.
Earlier this year, Poland appealed for international donations to help preserve the site. Britain and Germany, among others, have offered financial help.
In January the museum will celebrate the 65th anniversary of the camp's liberation by the Soviet Red Army. It hopes to open a new exhibition in the former prisoners' barracks chronicling the liberation.