Symbolic execution is a program analysis technique that can automatically explore and analyse paths through a program. While symbolic execution was initially introduced in the seventies, it has only received significant attention during the last decade, due to tremendous advances in constraint solving technology and effective blending of symbolic and concrete execution into what is often called dynamic symbolic execution. Dynamic symbolic execution is now a key ingredient in many computer science areas, such as software engineering, computer security, and software systems, to name just a few. In this talk, I will discuss recent advances and ongoing challenges in the area of dynamic symbolic execution, drawing upon our experience developing several symbolic execution tools for many different scenarios, such as high-coverage test input generation, bug and security vulnerability detection, patch testing and bounded verification, among many others.