The human brain is not able to realize neither nature norappearance, nor the scale of black holes. At the same time, many people do not even know that virtually any object can turn into this space object. Even our planet, if it is squeezed with sufficient force to the size of a peanut nut. This effect is associated with the concept of the Schwarzschild radius. With the reduction of the object with the condition of preserving the previous mass, it is transformed into a black hole (of course, on a certain scale). So, if you squeeze the Sun to the size of a small town, it will also turn into a black hole.
Of course, not every black hole hastiny size. For example, recently appeared photos of the object M87 quite impressive. The mass of this black hole is theoretically equal to the mass of 6.5 billion of our Suns. Its size and gravity is simply impossible to imagine, even having received visual numbers. However, a clear and vivid visualization of the Youtube channel morn1415 was published. Although the power and influence of a cosmic phenomenon on the surrounding space and objects are simply not amenable to awareness.