Man Rig - Mercedes Ener-G-Force

This scale model built by designers at the Mercedes-Benz Advanced Design Studio in Carlsbad, California is designed to capture and store rainwater on the roof of the vehicle through what you're likely thinking is the roof rack. It's actually the collection point for the "hydro-tech converter" which creates hydrogen power that is eventually sent to one of the four wheel-hub motors.

LINK (via: Expedition Portal)