The music festival Lollapalooza returned to Chicago in July for a four-day event with COVID-19 measures in place. All attendees were required to show proof of vaccination or a recent negative test to get in, and those who weren't vaccinated had to wear masks the whole time, according to the festival's website. On the third day of the festival, Lollapalooza began requiring masks in all indoor spots and recommended that everyone attending bring masks for the last two days.More days-long music festivals are planning to return in the coming months, like Bonnaroo, Austin City Limits, and Outside Lands.Lauren Leegard went to Lollapalooza — her first music festival ever — last weekend, and she told Insider she was anxious about being around so many people. This year, about 100,000 people went to Lollapalooza each day, NBC Chicago reported.There were tons of people which was absolutely insane seeing after the lockdown for such a long time, Leegard told Insider, adding that being fully vaccinated against COVID-19 made her feel better. I met new friends and had face-to-face connections with random people even if I would never talk to them again, Leegard said. I loved seeing people having fun and what they were wearing and how excited they were for the same artist I was coming to see!Leegard said her weekend of music exceeded her expectations of Lollapalooza. I enjoyed every single second of it, even if it got a little chaotic, Natalie Mars told Insider. I'm exhausted mentally and physically, but ready to go again next year.Mars said that she and her whole festival group had been fully vaccinated prior to attending Lollapalooza.It was a really uplifting experience that was all about supporting the people around you, she added. Hard Summer, the first big music festival to return to Los Angeles, took place at the NOS Event Center in San Bernardino on Saturday and Sunday, and 160,000 people showed up, the LA Times reported.Hard Summer said in a statement that the event was entirely outdoors and encouraged attendees to wear masks.Masks were free at information booths, and there were nearly 500 places where attendees could wash or sanitize their hands, according to the same statement.I hate to be the person to admit that I actually really enjoyed being around people and seeing my favorite artists perform after so long, Boyt said in an interview with Insider. There was so much great energy cultivated inside the event center.Boyd said she was fully vaccinated before the festival. Everyone was so happy and vibing with each other, Boyt said. It's definitely something I think we all missed. Rolling Loud didn't require vaccinations or masks for the event but encouraged both, according to the festival's website.