Ten Days' Wonder

Ten Days' Wonder (French: La Décade prodigieuse) is a 1971 French-Italian psychological thriller and murder mystery directed by Claude Chabrol. The film adapts Ellery Queen's 1948 novel of the same name, transposing the story to France and replacing the book's detective Ellery Queen with a new investigator character named Paul Régis.

The cast is led by Michel Piccoli, Anthony Perkins, Marlène Jobert and Orson Welles. Perkins had already appeared in Chabrol's The Champagne Murders (1967), while he and Welles had worked together on several earlier films, including the Welles-directed The Trial (1962). Written by Paul Gégauff and Paul Gardner, the 110-minute film was released in France in 1971.