Like a lot of young kids, Stephen Wiltshire found comfort in the pages of a sketchpad. Born in 1974 to West Indian parents, the London native faced some unique challenges early on. While most kids start uttering words within their first two years, Wiltshire was mute. At age 3 he was diagnosed with autism. Unable to communicate his thoughts and feelings, Wiltshire channeled his energy onto blank pages. "When I was a young boy, I couldn't speak and drawing was my way of expressing myself," he says via email. "I drew animals, London buses, and sometimes demolitions of large buildings as well. It helped me to say what I couldn't with words."

Fast-forward 45 years, and not only has Wiltshire continued the practice of self-expression through art, but he's become one of the most successful and renowned artists in Britain and beyond. His commissions have four- to eight-month waiting lists, and he's routinely swarmed by flashbulb pops and fans clamoring for autographs, as is evident in the trailer for his upcoming feature length documentary, "Billions of Windows." And while the journey to his present-day triumph wasn't exactly simple or straightforward, Wiltshire's unique story has kept the world captivated for decades.