Magicians have protested against a new exhibit in a Wisconsin museum giving away the secret to one of illusionist Harry Houdini's most famous tricks.
The AKA Houdini exhibit warns visitors that secrets are revealed
The exhibit at the Outagamie Museum in Appleton, Wisconsin shows how Houdini performed his "Metamorphosis" trick.
In the illusion Houdini - supposedly handcuffed in a sack and locked in a trunk - miraculously switched places with an assistant on the outside.
Some members of the Magic Circle have been angered by the museum's decision.
Illusionist David Copperfield has reportedly expressed his disapproval, along with lesser-known practitioners of the craft.
"This is a very, very passionate thing that magicians feel about," said Ronald "Rondini" Lindberg. "What the museum is doing is wrong."
However, curator Kimberley Louagie defended the museum's actions.
Ehrich Weiss - later Harry Houdini - was born in Budapest in 1874
"We didn't feel like we were exposing anything, because this information is readily available," she said.
"By telling people how this trick works, we're giving people a deeper meaning of Houdini."
Teller, one half of magical duo Penn and Teller, said people who see the Houdini exhibition would still be baffled if they watched a similar trick being performed at a show.
The AKA Houdini exhibit features 38 artefacts, 190 documents and "hands-on" displays that include handcuffs, lock picks, a straitjacket and a jail cell.
The part of the exhibit that shows how tricks are actually performed is in a backstage area.
The entrance bears a sign warning visitors not to enter if they do not want to know how Houdini achieved his baffling illusions.
Houdini was born Ehrich Weiss in 1874 in Budapest, Hungary. His family moved to Appleton when he was four and stayed four years.
He died on 31 October 1926 - Halloween - of a ruptured appendix.
If you do not want to know how Houdini performed his Metamorphosis trick, stop reading here.
The Metamorphosis trick uses a device known as the substitution trunk, which has a secret panel that allows its occupant to sneak out.
Having extricated himself from the sack in which he was tied, Houdini would climb out of the hidden door and crouch behind a curtain lifted by his assistant.
The magician and his assistant would then change places, Houdini appearing behind the curtain as the assistant disappeared into the box.
The assistant would then emerge from the box and sack wearing a different costume.