The Hollow Spire is a detective novel by Maurice Leblanc particularly successful in 1909. It retraces the Norman adventures of Arsène Lupin in the footsteps of the legendary treasure of the Kings of France. Historically, the secret of the Spire would have been transmitted since 56 BC. Joan of Arc would have told about it to the King, while Henri IV swore 'by the secret of the Spire. The famous Man in the Iron Mask would have held information, and Louis XVI is said to have transmitted a message concerning the secret to Marie-Antoinette in her prison in the Temple. In his novel, Maurice Leblanc sets the treasure inside the Aiguille Creuse of Étretat.