  We classify the Hamiltonians $H=p_x^2+p_y^2+V(x,y)$ of all classical
superintegrable systems in two dimensional complex Euclidean space with
second-order constants of the motion. We similarly classify the superintegrable
Hamiltonians $H=J_1^2+J_2^2+J_3^2+V(x,y,z)$ on the complex 2-sphere where
$x^2+y^2+z^2=1$. This is achieved in all generality using properties of the
complex Euclidean group and the complex orthogonal group.
