In 2003, Bernal and Sánchez showed that any globally hyperbolic manifold M has a smooth embedded three-dimensional Cauchy surface, and furthermore that any two Cauchy surfaces for M are diffeomorphic. In particular, M is diffeomorphic to the product of a Cauchy surface with R . It was previously well known that any Cauchy surface of a globally hyperbolic manifold is an embedded three-dimensional C 0 submanifold, any two of which are homeomorphic, and such that the manifold splits topologically as the product of the Cauchy surface and R . In particular, a globally hyperbolic manifold is foliated by Cauchy surfaces.