It's unlike any Merc we've ever seen. Scrap that, it's unlike pretty much any vehicle that we've ever seen - outside of science-fiction movies anyway - and the Mercedes Ener-G-Force Concept has a name as smart as the idea itself. Modelled around their G-Class, its roof has been sculptured to collect rainwater to power the hydrogen cells for 500 miles of pollution-free driving. Mad Max is not included.