  We study bifurcations of a three-dimensional diffeomorphism, $g_0$, that has
a quadratic homoclinic tangency to a saddle-focus fixed point with multipliers
$(\lambda e^{i\vphi}, \lambda e^{-i\vphi}, \gamma)$, where
$0<\lambda<1<|\gamma|$ and $|\lambda^2\gamma|=1$. We show that in a
three-parameter family, $g_{\eps}$, of diffeomorphisms close to $g_0$, there
exist infinitely many open regions near $\eps =0$ where the corresponding
normal form of the first return map to a neighborhood of a homoclinic point is
a three-dimensional H\'enon-like map. This map possesses, in some parameter
regions, a "wild-hyperbolic" Lorenz-type strange attractor. Thus, we show that
this homoclinic bifurcation leads to a strange attractor. We also discuss the
place that these three-dimensional H\'enon maps occupy in the class of
quadratic volume-preserving diffeomorphisms.
