Stephen has a "camera" mind due to the wiring in his brain because of Autism. He's renowned amongst the great architects and engineers of the world. He takes quick 10-15 min fly-overs of major global cities (no pen or paper) and then draws (panoramic) the entire city skyline building for building and detail for detail in just days.
What a beautiful mind. I've heard of these Savants before and it is indeed strange. Life can work in odd and mysterious ways. He has his own art gallery in the UK in Piccadilly Circus and the National Gallery behind Her Majesty's Theater. I will pay a visit next time I'm in London.

Stephen's Website