  We describe a simple technique for generating solutions to the classical
field equations for an arbitrary nonlinear sigma-model minimally coupled to
gravity. The technique promotes an arbitrary solution to the coupled
Einstein/Klein-Gordon field equations for a single scalar field $\sigma$ to a
solution of the nonlinear sigma-model for $N$ scalar fields minimally coupled
to gravity. This mapping between solutions does not require there to be any
target-space isometries and exists for every choice of geodesic computed using
the target-space metric. In some special situations -- such as when the
solution depends only on a single coordinate (e.g. for homogeneous
time-dependent or static spherically symmetric configurations) -- the general
solution to the sigma-model equations can be obtained in this way. We
illustrate the technique by applying it to generate Euclidean wormhole
solutions for multi-field sigma models coupled to gravity starting from the
simplest Giddings-Strominger wormhole, clarifying why in the wormhole case
Minkowski-signature target-space geometries can arise. We reproduce in this way
the well-known axio-dilaton string wormhole and we illustrate the power of the
technique by generating simple perturbations to it, like those due to string or
$\alpha'$ corrections.
