FRANKFURT, GERMANY - SEPTEMBER 15: CEO of Porsche AG Dieter Mueller presents Porsche Mission E during a Daimler event ahead of the IAA Frankfurt Motor Show in Frankfurt, Germany on September 15, 2015. The Frankfurt International Motor Show starts on Thursday, and nearly one million visitors are expected to view the latest must-have vehicles and motoring technology from over 1,000 exhibitors in a space equivalent to 33 soccer fields. (Photo by Mehmet Kaman/Anadolu Agency/Getty Images)
