Black holes are extremely dense regions in space where gravity is so strong that nothing, not even light, can escape its pull. They are formed when massive stars collapse in on themselves at the end of their life cycle, creating a singularity with infinite density at the center. Black holes have a boundary called the event horizon, beyond which nothing can escape. They are thought to play a crucial role in the evolution of galaxies and the universe as a whole. Research in this area focuses on understanding the physics of black holes, their properties, formation, and the ways in which they interact with their environment.