Black holes are all the rage these days, and for very good reason . They are shrouded in mysteries that a great many smart people are working hard to unravel. Black holes have some truly strange and mind-bending properties, the subject of quite a few Kurzgesagt videos . But what is a black hole really? In this article I'll try to give you a very simple intuition with physics you might know from high-school. If you are impatient, the main punchlines are given in orange below. Newton, meet Einstein We know that black holes have something to do with gravity. So let's start with Newton's formula for the gravitational force between two masses separated by a distance $r$, \[ F = \frac{G m_1 m_2}{r^2} . \] where the force $F$ is attractive. We also know from school that the work done by a force is given by \[ Work = Force \times distance. \] If the masses $m_1$ and $m_2$ were close together initially we'll have to do some work against the gravitational force between them