Are Black Holes Real

Various eminent scientists explain the current knowledge of Black Holes and try to answer the question, do they really exist? New discoveries are challenging everything we know about black holes -- astronomers are beginning to question if they even exist. The latest science tries to explain how they work & what they look like, despite the fact we've never actually seen one.
The two great theories of Einstein's General Relativity and Quantum Mechanics don't work together to explain Black Holes which is a big problem. Other theoretical constructs such as Gravastars and Planck stars have been postulated but proving their existence is just as difficult as that of Black Holes. So where next?