To celebrate the Fourth of July, we pick 20 tunes that are vying for the distinctly American honor of this year's Song of the Summer. We're talkin' Iggy Azalea, Charli XCX, Ariana Grande, Jason Derulo, 2 Chainz, Usher, Pharrell Williams, Calvin Harris, Sam Smith, Lowell, Chvrches, Royksopp & Robyn, Future Islands, Avey Tare's Slasher Flicks, Hamilton Leithauser, The Casket Girls, Nicki Minaj, Lana Del Rey, Sia, 5 Seconds of Summer, DJ Snake & Lil Jon, Ed Sheeran and many more! Actually, that's a lie. There are no more than the artists we just mentioned