Why we underestimated him: We didn't think that one of the dancers/hype men for the group Digital Underground would go on to become one of the greatest rappers of all-time.

When he proved us wrong: When he launched a solo career in 1991 and dropped his debut, 2Pacalypse Now, an album that tackled all sorts of social issues like poverty, racism, and teen pregnancy.

Though 2Pac's first two solo efforts, 2Pacalypse Now and 1993's Strictly 4 My N.I.G.G.A.Z., didn't launch him into the spotlight immediately, he transformed into a star within just a few years. In 1995, his third album, Me Against the World, topped the Billboard 200 chart when it was released, as did his Death Row Records debut, All Eyez on Me.

To date, he has sold more than 75 million albums total (including his posthumous releases) and is obviously considered one of the all-time rap greats. And to think, he used to be one of the guys who played the background in a rap group...