  We discuss the four-dimensional target-space interpretation of bosonic
strings based on gauged WZW models, in particular of those based on the
non-compact coset space $SL(2,{\bf R})\times SO(1,1)^2 /SO(1,1)$. We show that
these theories lead, apart from the recently broadly discussed black-hole type
of backgrounds, to cosmological string backgrounds, such as an expanding
Universe. Which of the two cases is realized depends on the sign of the level
of the corresponding Kac-Moody algebra. We discuss various aspects of these new
cosmological string backgrounds.
