Closed hyperbolic manifolds are proven to minimize volume over all
Alexandrov spaces with curvature bounded below by $-1$ in the same
bilipschitz class. As a corollary compact convex cores with totally
geodesic boundary are proven to minimize volume over all hyperbolic
manifolds in the same bilipschitz class. Also, closed hyperbolic
manifolds minimize volume over all hyperbolic cone-manifolds in the
same bilipschitz class with cone angles $\le 2\pi$. The proof uses
techniques developed by Besson-Courtois-Gallot. In $3$ dimensions,
this result provides a partial solution to a conjecture in Kleinian
groups concerning acylindrical manifolds.