Since the days of clashing sound systems trying to out-thump each other at New York City park jams, hip-hop has always been a competitive sport. Peace, love, unity and having fun—and crushing wack MCs into dust.

In a culture densely populated with supersized egos and brimming with pride (for one’s borough, one’s city, one’s crew and one’s own pen game) and where boasting is the point, clashing head-to-head, rhyme-for-rhyme is not only inevitable—it’s encouraged.

Rap rivalries have blessed us with hot lines and hotter songs. They’ve made some careers and dismantled others. Most of all, artist feuds have provided listeners with some of the most rewind-worthy headphone moments of the past 40 years and sparked round after round of debate: Who tore it better?

Are you on Team “Takeover” or Team “Ether”? Eminem or Machine Gun Kelly?

Steel sharpens steel. But, unfortunately, rap beef has proven to be a double-edged sword.

Fans certainly don’t want staged disputes, but when artist feuds spill off wax and onto the streets, leading to physical confrontation, the entertainment is far from worth it.

Looking back over the history of hip-hop’s many wars (of words), XXL plucked 20 of the most important rap rivalries of all time, highlighting the most scathing diss songs these grudge matches yielded and breaking down the origins and resolution (or non-resolution) of each beef. Let's get it. —Luke Fox

See 20 of the Most Important Hip-Hop Rivalries