abstract: Given a closed oriented manifold M, the spherical volume of M is a topological invariant introduced by Besson-Courtois-Gallot in their work on the entropy rigidity problem. The spherical volume naturally corresponds to a volume minimization problem inside a quotient of the Hilbert sphere. The main result we will discuss is that if M is negatively curved, then its spherical volume is equal to the volume of a minimal variety inside a quotient of the Hilbert sphere. Some important tools involved in the construction are the theory of metric currents, and properties of the regular representation of hyperbolic groups.