Musée des Arts et Métiers

This guide to the Musée des Arts et Métiers in Paris follows Léon Foucault's pendulum from its first public demonstration at the Panthéon in 1851, when crowds gathered to watch the swing prove the Earth itself was turning, to its move into the choir of this former priory in 1855. It also traces what happened one April morning in 2010, when the cable holding the original sphere gave way, and how a novelist later staged a fictional death in this same nave. Look up at the replica now tracing the same slow arc above the floor.