Abstract.  I will discuss two types of singularities in amplitudes caused by null geodesics in AdS and their resolutions by stringy effects. Certain Landau singularities are resolved by the Gross-Mende effect, and null singularities near the black hole photon sphere are resolved by stringy tidal effects. Interpretations of these singularities and their resolutions in the context of the AdS/CFT correspondence and their generalization to asymptotically flat spacetime will also be discussed.