How Shenzhen, China, became the electric car capital of the world

China now produces nearly three-quarters of the world's electric cars, and no city embodies that dominance more than Shenzhen, home to industry giant BYD. Once known as The World's Factory," the city of 20 million people has transformed into a global hub of clean transportation and high-tech innovation. As The World's Jeremy Siegel reports from the city, that shift has roots in Apple's decision to move production of the iPhone to Shenzhen in the early 2000s.