AdS_{3} Pure Gravity and Stringy Unitarity.

We construct a unitary, modular-invariant torus partition function of a two-dimensional conformal field theory with a Virasoro primary spectral gap of Δ_{*}=[(c-1)/12] above the vacuum. The twist gap is identical, apart from two states O_{*} with spin scaling linearly in the central charge c. These states admit an AdS_{3} interpretation as strongly coupled strings. All other states are black hole microstates.