The sky's the limit with Cadillac's new convertible concept. It's called the Ciel, pronounced "C-L" which is French for sky. The four-seat convertible takes Cadillac's Art and Science design to a whole new level of luxury. The Ciel is powered by a twin-turbocharged version of the 3.6-liter Direct Injection V6 with a hybrid system utilizing lithium-ion batteries.