"Tupac Shakur was an angel, Makaveli was a thug." -- Shock G, 2011

Today marks the 15th anniversary of Tupac Amura Shakur's death from his fatal injuries he suffered after being shot multiple times on Sept. 7, in Las Vegas. After attending a Mike Tyson-Bruce Seldon boxing match at the MGM Grand, the late rapper was a passenger in a car driven by Death Row Records CEO Marion "Suge" Knight when another car pulled alongside it and a gunman fired 14 bullets into their vehicle. Tupac was hit four times -- twice in the chest, once in the arm, and once in the thigh. Knight was grazed by bullets but was otherwise didn't sustained any life-threatening injuries.

The fallen rapper was only 25 years old when he passed away at UMC's Trauma Center surrounded by his family, including his mother, Afeni Shakur. In a strange twist, Tupac's presumed killer, Orlando Anderson, a member of the Los Angeles-based Crips street gang, was murdered in May 1998. Both homicides remain unsolved.

Fifteen years after Tupac's untimely death, we celebrate the music of hip-hop's most polarizing figure and the legacy that he left behind that is still immeasurable in popular culture.

In his brief career, 2Pac recorded five solo albums and one group album as a member of Thug Life. His first appearance on the hip-hop scene came when he was a member of the Oakland, Calif.-based rap group Digital Underground. But it was on his 1991 debut album '2Pacalypse Now' that his talent as an outspoken MC was evident. One standout track on the LP was the somber 'Brenda's Got a Baby,' which addressed the issue of teen pregnancy and the plight of the black family.

When 'Pac released 'Strictly 4 My N----Z' in 1993, black communities in Los Angeles were rebuilding in the aftermath of the 1992 L.A. Riots. His lyrics were militant and fiery as he encouraged black empowerment, particularly on 'Last Wordz' where he rapped, "United We Stand, divided we fall / They can shoot one n---a, but they can't shoot us all." On the flip side, he also had positive songs like 'Keep Ya Head' where he celebrated motherhood and black pride. On 'I Get Around' he openly admits that he's a player and doesn't wife groupies.

Out of all of his albums, 'Me Against the World' (1995) and 'All Eyez on Me (1996) are probably 2Pac's most noteworthy collections. On 'Me Against the World,' the rapper is reflective as he asks for forgiveness for his past sins. The album's centerpiece, 'Dear Mama,' is his apologetic ode to his mother for all of the pain he has caused her through the years. In stark contrast, the 'All Eyez on Me' album is defiantly angry and boastful. Of course, much of the anger was directed towards the east coast and the late Notorious B.I.G. who he felt betrayed him. The east coast/west coast rivalry continued after Tupac's death, which led to Biggie being slain in May 1998 in a drive-by shooting in Los Angeles. Sadly, his murder remains unsolved, as well.

Then a few months after 2Pac's untimely death, Death Row Records released 'The Don Killuminati: The 7 Day Theory.' Pac adopted the name Makaveli from Niccolò Machiavelli who was a political theorist that advocated faking one's death to fool his enemies. The album fueled conspiracy theories that the now deceased rapper was alive and hiding somewhere in a foreign country waiting for the perfect time to return. But Tupac's mentor, Shock G of Digital Underground, insists that the late rapper is neither alive nor Machiavellian.

"I don’t recognize my friend Tupac when I listen to Makaveli," he told Mlive.com. "I enjoy those records but I don’t really recognize my friend in there; Makaveli was only a character, that’s what Shock G wants the world to remember. I remind them that, that’s not who Tupac was. Just like Bruce Wayne ain’t Batman, Bruce Wayne is Bruce Wayne, Batman is Batman. Tupac Shakur was an angel, Makaveli was a thug."

In subsequent years, Tupac's legacy has grown even more stronger. There have been several posthumous albums, DVDs, poetry books and a clothing line released in his name. To date, 2Pac is the best selling hip-hop artist of all time with well over 100 million record sold and still counting. In film, an excellent bio-documentary about his life, 'Resurrection,' was nominated for an Oscar. In 2010, the Library of Congress immortalized Shakur’s timeless classic ‘Dear Mama’ into the National Recording Registry.

Watch the Tupac Shakur 'Dear Mama' Video

Tupac's music and legacy continues to inspire some of today's biggest rappers as evident in a recent Boombox article. Miami rapper Rick Ross said, "Tupac is more relevant than ever. I think his legacy will never tarnish, his emotion is still unmatched. I think we need to make sure we express that Tupac was a very intelligent, great speaker. He was very intellectual and we gotta continue [influencing] our young men [to be] leaders and speak their mind. That's what we miss the most about Tupac."

Snoop Dogg, who was 2Pac's labelmate on Death Row Records, concurs with Ross's sentiments. "His legacy is deeper than people could ever imagine," he said. "I been all over the world and the Tupac legacy is so deep. You got people believing that he's still here. He gave people a different train of thought. You can be a thug, but be an intelligent thug. I see gangsters now walking around with laptops and becoming smarter. I attribute that to him because he was a thinker. He made people that were around him think."

In the end, Tupac was all things to many people: he was an ex-con, a charismatic actor, an activist, a misogynist, a lyricist, a son, a brother and a revolutionary. So, 15 years later, Tupac Shakur is not dead. He lives inside all of us, and is still very much appreciated.

Watch the Tupac Shakur 'I Ain't Mad at Cha' Video