Do black holes really exist or is it just a fig of scientist's imagination,

They say black holes have such an intense gravitational pull, that even light cannot escape, Oh my God! so if light cannot bounce off them, then how are they going to look at it using giant earth size telescopes?
http://www.huffingtonpost.co.uk/2013/07/09/black-hole-event-horizon-telescope_n_3565479.html


So what are black holes then? and why do they exist? and how are they made, or created, and who creates them or what creates them, what are they made of, some questions I need answers for,