Firefly is one of the most underrated festivals that occurs every year. Taking place in Dover, Delaware per usual, the 4-day festival has a slew of legends headlining this year such as Paul McCartney and Kings Of Leon, as well as the likes of The Killers, Snoop Dogg, Steve Aoki, Zedd, Kid Cudi, Logic, Run The Jewels, Jon Bellion and much more. The reason Firefly is so great is because of the variety of genres that perform. How often will you see Run The Jewels and Paul McCartney perform together? I rest my case. See the lineup and buy passes here.