  It is shown how, within the framework of general relativity and without the
introduction of wormholes, it is possible to modify a spacetime in a way that
allows a spaceship to travel with an arbitrarily large speed. By a purely local
expansion of spacetime behind the spaceship and an opposite contraction in
front of it, motion faster than the speed of light as seen by observers outside
the disturbed region is possible. The resulting distortion is reminiscent of
the ``warp drive'' of science fiction. However, just as it happens with
wormholes, exotic matter will be needed in order to generate a distortion of
spacetime like the one discussed here.
