SATURDAY, SEPTEMBER 15 & SUNDAY, SEPTEMBER 16 - ATLANTA'S PIEDMONT PARK Also includes: Khalid, Thirty Seconds to Mars, Gucci Mane, Janelle Monáe, Portugal. The Man, The Revivalists, Foster the People, Kacey Musgraves, Sylvan Esso, BØRNS, First Aid Kit, Billie Eilish, Rainbow Kitten Surprise,...