One of the key components of any formidable emcee has long been the ability to engage in lyrical battle. So here's a look at the 20 nastiest diss tracks in hip-hop history in the gallery below.

For decades, rap beefs have brewed and festered on wax—from the infamous "Bridge Wars" between Boogie Down Productions and the Juice Crew, to more nefarious beefs between Jay-Z and Nas, to big recent battles in the internet age, like the one between Remy Ma and Nicki Minaj, or Pusha T's slaughtering of Drake on "Story of Adidon."

Some beefs have spilled off wax (see Biggie and Tupac or Jeezy and Gucci Mane). Others have pretty much ended careers—Tim Dawg, anyone? Still others simply provided fans with a reminder of their favorite rapper's lyrical skills, or sometimes, sadly, the lack thereof.

We've skimmed through some of hip-hop's biggest word wars to come up with a list of rap battles that spans eras. Some of them have long since been squashed, while others have lingered on for years. And in addition to describing the most brutal lines in the track, we've also provided a history fo the beef to show you how it escalated to that point. But one thing is certain, rap beefs have been keeping hip-hop fans entertained for years, and rappers on their lyrical toes in the process.

Take a look at the Boombox's list of some of the nastiest diss songs in history.