A black hole is an extremely dense and massive object in space. Its gravity is so strong that it warps the spacetime around it, creating a region called the event horizon beyond which nothing can escape. Black holes are formed from the remnants of massive stars that have collapsed inward due to their own gravity. Despite their name, black holes are not black in the sense of being empty; rather, they are surrounded by a glowing accretion disk of matter that is being pulled towards them.