Visitors look at a Porsche 911 Carrera 4 at the Frankfurt Auto Show 2013, in Frankfurt, Germany, 19 September 2013. The Frankfurt Auto Show is the World's largest. It features the latest releases and concept automobiles from Porsche, BMW, Mercedes, Audi, Lamborghini, Bugatti, Ferrari and much more. (Photo by Horacio Villalobos/Corbis via Getty Images)
