The painting The Origin of the World was hidden behind another painting

The Origin of the World is a painting by Gustave Courbet painted in 1866 at the request of a Turkish diplomat. Having become the property of the psychoanalyst Jacques Lacan, it was concealed in a double-bottomed frame fitted with a mask painted by André Masson. The work finally joined the collection of the Musée d'Orsay in 1995.