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Lollapalooza is 20 years strong and has no plans to slow down any time soon.

This past weekend, the festival kicked off its 2017 four-day run at Grant Park in Chicago, Illinois. Of course there was an awesome lineup featuring Blink-182, Machine Gun Kelly and more, but there were also a ton of surprises (and not-so-surprises) that you may have missed. Lucky you, we rounded them all up for you. Here's some of the highlights of Lollapalooza 2017!

Read more: Music festival featuring Paramore, PVRIS, Chance the Rapper, more canceled

1. Liam Gallagher has a diva moment

Early on during the first day of Lolla, Oasis' Liam Gallagher cut his set short and fans were not pleased.

Read more: Liam Gallagher storms off stage 20 minutes into Lollapalooza set, crowd is pissed

Gallagher explained the incident away in a tweet blaming it on his voice, however.

2. Mass evacuation on Friday

Unfortunately, Liam Gallagher's set wasn't the only one cut short on Thursday. Severe weather forced the entire festival to evacuate—just minutes into headliners Lorde and Muse's sets.

Read more: 22,000 fans evacuated after stage fire at Tomorrowland festival

Like Gallagher and both headliners were left "gutted":

3. The Killers making up for it on Friday!

To help heal the wounds of fans still hurt by the abbreviated Muse set, the Killers did a stunning cover of Muse's "Starlight."

Read more: The Killers’ Brandon Flowers talks negativity at band’s start: “It came from a place of insecurity”

The band also covered Smashing Pumpkins' "Disarm" and Joy Division's "Shadowplay" during their set. Watch the full set right here.

4. An incredible headlining set from Blink-182

While the Killers were covering Muse, Blink-182 were on the other side of the park absolute crushing their headline set, complete with fireworks. Watch their opening song "Feeling This" below, and check out the whole performance here!

Read more: Blink-182’s already talking about what their next album will sound like

5. The cell phone thief of Lollapalooza is caught

According to NBC Chicago, the Chicago PD recovered all the stolen items from a thief who reportedly stole 60 phones over the weekend! Not exactly music news, but we'd definitely watch this episode of Law & Order.

6. Chance The Rapper brings out Vic Mensa

He may not be a part of the scene per se, but Chance The Rapper was without question the most anticipated set of his hometown festival. As if his set could get any better, he brought out fellow rapper Vic Mensa for a guest spot. Mensa also pulled off a surprise set that day at Lolla, announced just eight hours before!

The guest appearance also squashed a year-old beef. Nothing like music bringing people together, right?

6. Foo Fighters' extra-long surprise set

Surprises on surprises—Foo Fighters made an appearance at a last-minute aftershow, despite the fact that they weren't on Lollapalooza's official lineup (although we wish they were!). And they certainly took advantage of their time: The band crushed a three-and-a-half hour set, covering an entire career's worth of material. Perry Farrell of Jane's Addiction even hopped on for a song!

Read more: Former Foo Fighters drummer compares Dave Grohl to a schoolyard bully

7. Machine Gun Kelly's amazing set, featuring a Chester Bennington tribute

Machine Gun Kelly always crushes his live performance, and we would've killed to see him play to this huge festival crowd.

Read more: Coldplay’s Linkin Park “Crawling” cover and 9 other moving Chester Bennington tributes

The rapper recently debuted a tribute cover of Linkin Park's "Numb," and lucky audience members got to see him play it at his Lollapalooza set on Sunday.

8. Arcade Fire close the festival with another career-spanning set

Just because Lolla was ending didn't mean it had to slow down for a second. Arcade Fire closed out the festival with a headlining set that did service to their entire body of work, including hits like "Wake Up" and even a cover of John Lennon's "Mind Games" to close out their encore.

9. Charli XCX brings out Halsey for a Spice Girls cover

All of our favorite girls were out at Lolla! Charli XCX brought out Halsey as a surprise guest for a cover of the Spice Girls classic "Wannabe." Watch it below! Speaking of, if you haven't seen Charli XCX's "Boys" music video yet, trust us: Get on it.

WATCH: Brendon Urie, Oli Sykes, Jack Antonoff, more show up in Charli XCX’s star-studded “Boys” music video

That's all we have for you! Would you have killed to be at Lollapalooza? Did you attend this year? Tell us all about it in the comments!

Watch more: APTV's Tori Kravitz on Festival Etiquette