Emerson, Lake & Palmer - Karn Evil 9

Emerson, Lake & Palmer were progressive rock's first supergroup. Greeted by the rock press and the public as something akin to conquering heroes, they succeeded in broadening the audience for progressive rock from hundreds of thousands into tens of millions of listeners, creating a major radio phenomenon as well. Their flamboyance on record and in the studio echoed the best work of the heavy metal bands of the era, proving that classical rockers could compete for that arena-scale audience.