You cant see a black whole. But you can see matter and light that is bending and swirling around the black whole.. There is a "shell" around a black whole. The shell is created by Photons that are trapped. They are at a point were the escape volocity is 186,000 miles per second (about 670 Million miles per hour) So the light photons are trapped were they cant escape or be sucked in. You cant see the shell because the light photons never reach your Eye. So really the only thing that i know about to be visible is the light and/or matter that is swirling around the event horizon of the black whole.