  It is shown that time-independent solutions to the (2+1)-dimensional non-
linear O(3) sigma model may be placed in correspondence with surfaces of
constant mean curvature in three-dimensional Euclidean space. The tools
required to establish this correspondence are provided by the classical
differential geometry of surfaces. A constant-mean-curvature surface induces a
solution to the O(3) model through the identification of the Gauss map, or
normal vector, of the surface with the field vector of the sigma model. Some
explicit solutions, including the solitons and antisolitons discovered by
Belavin and Polyakov, and a more general solution due to Purkait and Ray, are
considered and the surfaces giving rise to them are found explicitly. It is
seen, for example, that the Belavin-Polyakov solutions are induced by the Gauss
maps of surfaces which are conformal to their spherical images, i.e. spheres
and minimal surfaces, and that the Purkait-Ray solution corresponds to the
family of constant-mean-curvature helicoids first studied by do Carmo and
Dajczer in 1982. A generalisation of this method to include time-dependence may
shed new light on the role of the Hopf invariant in this model.
