Black holes form when a massive star collapses under the force of its own gravity after exhausting its nuclear fuel. The star's core crunches into an infinitely dense point called a singularity, surrounded by an invisible boundary called the event horizon. Beyond the event horizon, gravity is so strong that nothing can escape, not even light. Black holes can have varying masses, from stellar ones formed by collapsing stars to supermassive black holes found at the center of galaxies. Key features of black holes include their immense gravitational pull, event horizon, Hawking radiation, and effects on the space-time fabric.
Imagine you are an astronomer giving a presentation about black holes. Describe the formation and key features of a black hole.