In the context of the gauge/gravity duality, the flux tube between a quark-antiquark pair in strongly coupled Yang-Mills theories is described by a Nambu-Goto string hanging in AdS spacetime from its boundary. I will talk on time evolution and nonlinear dynamics of the string in AdS_5 dual to N=4 supersymmetric Yang-Mills theory when the string is perturbed with finite amplitudes. I will firstly show that waves on the string show turbulent behaviors, and as a result cusps form on the string. I will then show if the perturbations are very strong, the initially connected string stretches infinitely, forms effective event horizons, and transitions to two separated strings dynamically.