On this day, September 29, in hip-hop history...

LaFace Records
LaFace Records

1998: Initially conceived as the companion album to an uncompleted theatrical film, Aquemini, OutKast's third studio LP, was released into stores on Sept. 15, 1998. Often considered by critics and fans alike as OutKast's finest effort, the album would be released to sterling reviews and critical success peaking at No. 2 on the Billboard charts on it's way to being certified double platinum by the RIAA.

With the title of the album being derived from a portmanteau of the group's two member's Zodiac signs—Big Boi (Aquarius) and André 3000 (Gemini)—Aquemini found OutKast continuing to swerve away from the gangster clichés of the day into a more spiritual realm of hip-hop.  Addressing  hardcore fans bristling at the group's newer left-field focus, André would address the situation on "Return Of The G," rapping "Return of the gangsta/ thanks ta them niggas that get the wrong impression of expression/ Then the question is 'Big Boi what's up with André.. Nigga /I'm feelin' better than ever what's wrong with you?" Continuing along with those ideas, the album focuses on themes of morality and addressed complex issues like drug abuse, self-destruction and ill-fated romance.

Stylistically, OutKast were as innovative as ever, employing live instrumentation, futuristic synthesizers and poetic lyricism to create an LP that sounded nothing like anything that was in popular music at the time. Produced primarily by the group themselves along with long-time Dungeon Family collaborators, Organized Noize and Mr. DJ, the group used eclectic and soulful sounds using elements of reggae, 1970s funk, jazz and even big band to score the album.

The album would also features some of their most indelible songs such as "Rosa Parks," Da Art Of Storyelling (Part I)" and Raekwon-assisted "Skew On The Bar-B." The latter song would help to shatter hip-hop's dogmatic regional boundaries by featuring an East Coast rapper, Raekwon, over 'Kast's southern-fried production at a time only a few years after the bloody aftermath of the infamous East Coast-West Coast "feud" of the mid-1990s.

20 years later, Aquemini enjoys a tall reputation by carving out a place in hip-hop that shattered regional boundaries and pushing forward into new avenues of artistic expression. The LP continues to win new fans to this day and remains not only one of the finest OutKast albums to-date but easily one of the greatest albums of the 1990s.

Here's the Ultimate Guide to Rappers With Acronyms in Their Name

More From XXL