If you run it back all the way to 1973, Aug. 11 to be exact, DJ Kool Herc changed the landscape of music forever while DJing at a back to school party in the Boogie Down Bronx. However, he didn't do it alone. The legendary DJ was accompanied by the likes of Coke La Rock, who took on the role of Master of Ceremony and helped get the crowd feeling right. At the very origin of the beloved genre and subculture known as hip-hop, the act of the duo played an integral role.

Such a tradition has carried on for years, with DJ Jazzy Jeff & the Fresh Prince even naming their sophomore album, He's the DJ, I'm the Rapper, after the phenomenon of duality, in 1988. As hip-hop continues to evolve over time, we've been blessed with a bountiful variety of duos, collaborations and partnerships, with each adding their own contributions to the game and reminding us that, as the idiom goes, good things come in twos.

When rappers join forces, either with a DJ, producer or another rapper, the result is typically as captivating as it is cogent, with some of the most unbreakable bonds coming in pairs. However, as history reminds us, some of the most compelling chapters often have to close and even the most iconic of duos have had to part ways, for one reason or another, or even for reasons unknown. However, the chemistry that manifests itself when two people work together exclusively for a given amount of time is unparalleled, particularly in rap, and as a result, has holds the power to imprint on history much like DJ Kool Herc and Coke La Rock did many moons ago.

While some of hip-hop's most dynamic duos are still riding together as strong as ever, such as Pete Rock & CL Smooth reuniting for a victory lap tour nearly three decades since they first teamed up, not every pair can (or wants to) stay the same today. Whether they were an official group or just friends and business partners who created something truly dope, a fallout can happen. Sometimes circumstances are simply out of one's control, such as the tragic loss of one-half of the duo, such as with Pimp C's death marking the end of UGK's legacy in its most potent form. Other times people just grow up or grow apart, such as with Andre 3000 expressing he's content with the work that he accomplished alongside Big Boi as part of OutKast.

Whatever the reason for a duo to dissolve when fate twists in such a direction, we're happily left with both the music and the nostalgic yearning for the two of a kind to step back into the booth together. Here are 20 examples of hip-hop duos that we miss, from Lil Wayne and Birdman to Jay-Z and Kanye West and more, with each holding a special place in history and in rap fans' hearts alike.

See 20 Memorable Hip-Hop Duos We Miss

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