  In this paper, we show that, if a group $G$ acts geometrically on a
geodesically complete CAT(0) space $X$ which contains at least one point with a
CAT(-1) neighborhood, then $G$ must be either virtually cyclic or
acylindrically hyperbolic. As a consequence, the fundamental group of a compact
Riemannian manifold whose sectional curvature is nonpositive everywhere and
negative in at least one point is either virtually cyclic or acylindrically
hyperbolic. This statement provides a precise interpretation of an idea
expressed by Gromov in his paper Asymptotic invariants of infinite groups.
