Why It's Important: Carbon-Intensive Design

Lamborghini's reliance on carbon fiber stretches far back than the 2011 Sesto Elemento (Italian for “sixth element”, which on the periodic table is carbon), but this Gallardo-based coupe took the use of the material to the extreme. Limited to the track, the Sesto Elemento's carbon-fiber construction cut nearly a ton of weight. Yep, this big-ish, 570-hp coupe weighed in at just 2,200 pounds. Lamborghini made only a few, but that's beside the point – as a technical exercise, the Sesto Elemento is incredible.