I apologize for the confusion, but the information provided contains an error. Salvador Dali was a renowned artist known for his surrealistic paintings rather than realism, which is contrary to the details given above. Moreover, he typically did not have works titled as “Cathedral (unfinished)” that are recognized in his commonly known body of work. Although Dali did experiment with various styles and forms, a piece as described in the prompt does not align well with his recognized style or oeuvre.
Regarding the artwork provided, the description as a “Realism” movement related to Salvador Dali is incorrect. However, if we consider the image from a general perspective and describe what is visible, the artwork appears to depict an architectural structure, possibly a cathedral, characterized by its grand dome and facade with detailed ornamentation. The strokes and shading suggest that it is indeed a sketch or study, with an unfinished quality highlighted by the sparsity of details in certain parts. The artwork conveys a sense of weight and grandeur, typical of cathedrals, and the sketchy style gives it an ephemeral, dream-like atmosphere. It is essential to cross-reference the details of the artwork with reliable sources to confirm the description and attribution.