Heavy thunderstorms forced day one of Lollapalooza to end early with headliners Lorde and Muse still on stage.
Concertgoers evacuated Chicago's Grant Park as the severe weather rolled in Thursday night. A short time later, the music festival made the cancellation announcement.
Singer Lorde, who was onstage at the north end of the park, tweeted after her set was called off that she had "the most spectacular show planned."
Matt Bellamy, lead singer of the band Muse, said on his Twitter page that officials made the band leave the stage after just three songs. Bellamy called it a nightmare and said he was "gutted."
The second day of Lollapalooza is expected to go ahead as scheduled Friday. Performers set for day two include blink-182, The Killers, DJ Snake and Run the Jewels.