  We study in some detail the properties of the mathematically correct
formulation of the classical Einstein-Rosen "bridge" as proposed in the
original 1935 paper, which was shown in a series of previous papers of ours to
represent the simplest example of a static spherically symmetric traversable
lightlike thin-shell wormhole. Thus, the original Einstein-Rosen "bridge" is
not equivalent to the concept of the dynamical and non-traversable
Schwarzschild wormhole, also called "Einstein-Rosen bridge" in modern textbooks
on general relativity. The original Einstein-Rosen "bridge" requires the
presence of a special kind of "exotic" matter source located on its throat
which was shown to be the simplest member of the previously introduced by us
class of lightlike membranes. We introduce and exploit the Kruskal-Penrose
description of the original Einstein-Rosen "bridge". In particular, we
explicitly construct closed timelike geodesics on the pertinent Kruskal-Penrose
manifold.
