The final touch? His signature.
Wiltshire said he was happy and excited to finally be finished with the drawing. The artwork will be shipped back to Wiltshire's London gallery to join his eight panoramas of other iconic cities.
All this week in "The Early Show"'s "A Beautiful Memory" series, Wiltshire had been drawing the panorama cityscape completely from memory, at Brooklyn's Pratt Institute.
CBS News correspondent Kelly Wallace reported it took just 20 minutes in a helicopter over New York for Wiltshire to commit details of the city's landmarks, including Central Park, the Statue of Liberty and the Empire State Building, to his remarkable memory. However, he didn't just recall the landmarks, Wallace remarked, he even knew the number of buildings that crowd midtown Manhattan.
Wiltshire is considered a prodigious savant, according to Dr. Darold Treffert, an expert on savants with autism, which means he is gifted, yet developmentally disabled. Wiltshire was diagnosed with autism as a child, and at an early age was hailed a prodigy for his ability to draw buildings in stunning detail.
Wiltshire, now 35, is an acclaimed artist for his body of work, but particularly for his sweeping panoramas of cities, such as London, Dubai, Tokoyo, Rome and Madrid.
However, Wallace reported, Wiltshire's favorite city is New York. And throughout his stay in the city he's found many inspirations, from Times Square to the Empire State Building, to a local fire station.
But it was the panorama that he was devoted to finishing, filling the 20-foot-long blank canvas with the skyline a bit more every day. And like the city admires, Wallace remarked, Stephen's vision of New York became an attraction all its own, as people flocked to the Pratt Institute to see him draw.
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But when he draws, does Wiltshire have an image already in his head?
Wiltshire said the image is his own.
He said, "I'm keeping away from pictures and photographs, and just do it just from memory."
And Wiltshire saved New York for his final panorama. He will now explore new creative directions for his genius.
Wallace remarked, "As New Yorkers, we say he saved the best for last."