  We explore physics behind the horizon in eternal AdS Schwarzschild black
holes. In dimension d >3, where the curvature grows large near the singularity,
we find distinct but subtle signals of this singularity in the boundary CFT
correlators. Building on previous work, we study correlation functions of
operators on the two disjoint asymptotic boundaries of the spacetime by
investigating the spacelike geodesics that join the boundaries. These dominate
the correlators for large mass bulk fields. We show that the Penrose diagram
for d>3 is not square. As a result, the real geodesic connecting the two
boundary points becomes almost null and bounces off the singularity at a finite
boundary time t_c \neq 0. If this geodesic were to dominate the correlator
there would be a "light cone" singularity at t_c. However, general properties
of the boundary theory rule this out. In fact, we argue that the correlator is
actually dominated by a complexified geodesic, whose properties yield the large
mass quasinormal mode frequencies previously found for this black hole. We find
a branch cut in the correlator at small time (in the limit of large mass),
arising from coincidence of three geodesics. The t_c singularity, a signal of
the black hole singularity, occurs on a secondary sheet of the analytically
continued correlator. Its properties are computationally accessible. The t_c
singularity persists to all orders in the 1/m expansion, for finite \alpha',
and to all orders in g_s. Certain leading nonperturbative effects can also be
studied. The behavior of these boundary theory quantities near t_c gives, in
principle, significant information about stringy and quantum behavior in the
vicinity of the black hole singularity.
