A closed geodesic in a Riemannian manifold is a geodesic which intersects itself in some point.
My question is
Does every negatively curved, locally symmetric space of finite volume have a closed geodesic?
This statement is said to be a well-known fact in an article I read, however, I have not been able to find a reference in standard books such as Helgasons book on symmetric spaces or Wolfs book on spaces of constant curvature.
Is it true? Why?