  We consider localization of gravity in domain wall solutions of Einstein's
gravity coupled to a scalar field with a generic potential. We discuss
conditions on the scalar potential such that domain wall solutions are
non-singular. Such solutions even exist for appropriate potentials which have
no minima at all and are unbounded below. Domain walls of this type have
infinite tension, while usual kink type of solutions interpolating between two
AdS minima have finite tension. Non-singular domain walls with infinite tension
might a priori avoid recent ``no-go'' theorems indicating impossibility of
supersymmetric embedding of kink type of domain walls in gauged supergravity.
We argue that (non-singular) domain walls are stable even if they have infinite
tension. This is essentially due to the fact that localization of gravity in
smooth domain walls is a Higgs mechanism corresponding to a spontaneous
breakdown of translational invariance. We point out that if the scalar
potential has no minima and approaches finite negative values at infinity, then
higher derivative terms are under control, and do not affect the cosmological
constant on the brane which is vanishing for such backgrounds. Nonetheless, we
also point out that higher curvature terms generically delocalize gravity, so
that the desired lower dimensional Newton's law is no longer reproduced.
