Mariah Carey is one of a kind. She's equally comfortable singing power pop ballads as she is churning out R&B hits, which is part of what's made her a mainstay on the charts for over 20 years. That versatility has been the secret to Mariah's longevity. Never afraid to change with the times, she's recorded straight-ahead pop, R&B, and hip-hop. Her five-octave vocal range makes her one of the strongest singers in history, and her stats prove it, as she's sold more than 200 million albums worldwide.