What is the significance of the event horizon in relation to a black hole?

The significance of the event horizon in relation to a black hole lies in its defining characteristic as the boundary surrounding the black hole. Specifically, the event horizon marks the point beyond which nothing can escape the gravitational pull of the black hole, not even light. This concept is crucial in understanding the nature of black holes and their behavior within the framework of general relativity.

The event horizon serves as a "point of no return" for anything that crosses it, leading to the singularity at the center of the black hole where gravitational forces become infinitely strong. The properties and implications of the event horizon are what distinguish black holes from other cosmic phenomena, making it a fundamental aspect of astrophysical studies related to these enigmatic objects.