abstract: Static spacetimes are solutions to the Einstein Field Equations featuring a very special metric structure (warped product). Such a structure induces a natural foliation of the spacetime into space-like slices which are all isometric to each other, so that the corresponding physical universe is static. We discuss the problem of the classification of such spacetimes, reviewing the main known results and distinguishing between the cases of positive, negative and zero cosmological constant. We then show how a recent comparison argument can be applied to prove some known and new characterizations of the model solution.