There will never be another Tupac Shakur. Who knew that back in 1991 after he made his musical debut with 2Pacalypse Now that the saggy jean-wearing, wide-eyed MC who rapped about the fictional teenaged Brenda and her baby would grow to be one of the most revered figures in modern American history? On Tuesday (September 13), the 15th anniversary of the day he died at age 25, it is clear that Tupac has transcended hip-hop, held by his generation in the same regard as inspirational musical figures like Bob Marley and John Lennon.

Tupac's 1996 shooting and death was the final act in a life often overshadowed by drama and controversy. On September 7, 1996, after attending a Mike Tyson heavyweight championship fight in Las Vegas (and then getting into a fight himself afterwards), the rap star was shot multiple times in a drive-by shooting. It wasn't the first time the enigmatic street poet came under fire. On November 30, 1994, Shakur was shot five times and, like a mythical urban superhero, checked himself out of the hospital against the doctor's orders, living to tell his tales through rap.

Through his music, storied acting career and overall public persona, Tupac Shakur had proved resilient, so his fans held hope that he would survive the 1996 attack that left him hospitalized for six days. But this time would be different. On Friday September 13, 1996, Tupac Amaru Shakur died due to respiratory failure and cardiac arrest. Authorities have yet to find his killer.

Born to two Black Panthers, Tupac understood poverty and black struggle, and he wasn't afraid to express it through his music. As intelligent, profound and articulate as he was in song, 'Pac also remained relatable, controversial and contradictory. So while tracks like "Brenda's Got a Baby," "Keep Ya Head Up" and "Dear Mama" were made to uplift, fiery anthems like "Hit 'Em Up," "Ambitionz Az a Ridah" and "Against All Odds" stood as chest-pounding, testosterone-filled thug anthems. Other hits like "I Get Around," "How Do U Want It" and "Toss It Up" celebrated Tupac's flirtatious side.

A double-threat, 'Pac went on to conquer Hollywood as well, beginning with a brief appearance in 1991's "Nothing But Trouble," starring Chevy Chase and Demi Moore. It was his 1992 role in the movie "Juice," however, that certified him a star. Playing the maniacal and villainous Bishop, 'Pac put his Thug Life persona on full display on the silver screen. He went on to land roles in films like "Poetic Justice" with Janet Jackson, "Above the Rim" and "Bullet," alongside Mickey Rourke.

In February 1995, the rapper/actor began serving a prison sentence at Clinton Correctional Facility in New York after he was sentenced on a sexual abuse charge in a rape case he faced the previous year. When he released his third solo album, Me Against the World, a month later, 'Pac became the first artist to score a #1 album on the Billboard 200 albums chart from behind bars.

Later that year, Death Row Records CEO Marion "Suge" Knight posted bail pending Tupac's appeal and signed the rapper to his label, where he went on to release his first double LP All Eyez on Me and, under the alias Makaveli, his The Don Killuminati: The 7 Day Theory (which came out months after his death). While he was creating what many agree was the best music of his career, this period in 'Pac's life was marked by the feud he ignited with the Notorious B.I.G. and Diddy's Bad Boy Records. B.I.G. was gunned down six months after Shakur, on March 9, 1997. While many speak of the two rap deaths in the same regard, there is no concrete evidence to link the two. B.I.G.'s murder is also unsolved.

After his death, Tupac's legacy lives, particularly with the eight posthumous albums that have been released, including a double-disc greatest hits collection. He has been immortalized in film, books and even college courses, as well as through the works of musicians who have come after him. Traces of 'Pac can be found in nearly almost every rapper from 50 Cent to T.I. Jay-Z, Eminem, Fabolous and Cam'ron have all sampled from Shakur, and non-rap artists like Justin Bieber have claimed to be fans.

In his death he has remained firmly rooted as a hip-hop legend, but at the same time his legend has surpassed musical genre. Tupac Shakur was more than a rapper or poet or a thespian; he is a motivator, an inspiration and an American classic — even in death.