CHICAGO (CBS) — The announcement for the 2016 dates of Lollapalooza — the annual music festival that fills Chicago’s grant park every summer — included a surprise: a fourth day.

Traditionally three days, the festival is expanding to four days in honor of its 25th anniversary. Lollapalooza 2016 will take place July 28th through July 31st.

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“There’s a lot of really great music coming out in 2016; with the abundance of talent that wanted to help us celebrate 25 years we got to thinking… ‘How are we going to fit all those great artists in one weekend?'” wrote Lollapalooza founder, Perry Farrell, in a press release. “Then we thought about what a special day Thursday has become. When the party can’t wait for the weekend, the movers and shakers make it happen on Thursday!”

Tickets giving music fans access to all four days of the festival will cost $335, with single-day tickets going for $120. Tickets go on sale spring 2016.

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Over the years, Lollapalooza has occasionally caused minor concerns, with doctors warning of the dangers of underage drinking and drug use. Park advocates have also voiced complaints about the damage the festival causes to Grant Park, but organizers have often addressed these problems.

Lollapalooza plans to feature over 170 bands over the course of four days, but has yet to announce a lineup. In previous years, headliners included the likes of Paul McCartney, Florence + the Machine, Eminem, Jane’s Addiction and The Smashing Pumpkins.

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