Black Hole, Everybody have some knowledge about this as it is the universe mysterious thing and no one know fully about him yet as we live very far away from the black Hole although the very nearest black hole is about is about 1000 light years apart.
This is an small GIF showing his existence and the center of black hole where one goes in never came back as it is called singularity.
It can be simply understand as when any planet is attracted towards the black hole due to its immense gravitational force then one thing happen that planet is moving towards its singularity without stoppage and breaking into pieces it just move into the singularity of Black Hole and never came back .
Even the light cannot come back through the black hole as it is enter into it. So singularity is basically that position where everything end up when light can't come back so leave the rest of the things as everything come in but no way out.
There may be the one way to cross the singularity that you have to travel with speed of light but no one can do that as it is impossible for to moving faster than speed of light.
This is how black Hole created when star dead then there is supernova explosion occurred as it's whole mass compress into the one point then Black Hole created but there is another thing is also there as Star converted into Black Hole only when his mass is 20 times greater than our Sun then and only it will convert into Black hole and if not so it will converted into White dwarf.