  We prove that if in a spacetime endowed with a merely continuous metric, a
complete partial Cauchy hypersurface has nonempty Cauchy horizon, then the
horizon is caused by the presence of almost closed causal curves behind it or
by the influence of points at infinity. This statement is related to strong
cosmic censorship and a conjecture of Wald. In this light, Wald's conjecture
can be reformulated as a PDE problem about the location of Cauchyh horizons
inside black hole interiors.
