Gravity's Final Victory

When a massive star runs out of fuel, it can no longer support itself against its own gravity. The core collapses. If the remaining mass exceeds about 3 solar masses, nothing can stop the collapse.

The boundary around a black hole is called the event horizon — the point of no return. Cross it and you would need to travel faster than light to escape. It is not a physical surface but a mathematical boundary. You would feel nothing crossing it, yet you would never come back.