Gates opened at 11 a.m. but fans started lining up much earlier.
The festival, which is in its 20th year, has called Grant Park home since 2006. More than 130 acts are scheduled to perform. Headliners include Eminem, Coldplay and Foo Fighters. The fest is also known for bringing newer bands to the public.
Lake Shore Drive and Columbus will be closed from Monroe to Roosevelt through Sunday. Also, the west sidewalk on Lake Shore Drive is closed from Monroe to Roosevelt. Pedestrians will not be allowed access to the Museum Campus tunnel. They will be redirected to the east side of Lake Shore Drive.
Lollapalooza founder and Jane's Addiction front man Perry Farrell kicked off the event Friday morning with a news conference.
"No one is really prepared for a show and an event of this importance and this magnitude. Back then 20 years ago, I expected to see maybe 10,000 to 20,000 weirdos showing up from town to town. And now I'm proud to say that we have 90,000 weirdos showing up here today in Chicago," he said.
Last year, Farrell said the festival expanded internationally. Next year the music fest will be celebrated in Brazil.
Jesse Parrish and Faith Peddie, and many others, are on the hunt for tickets for the sold out mega music festival.
" The big bads I want to see? My Morning Jacket?She wants to see the Perfect Circle real bad. I'd like to them too," said Parrish.
"I have been looking at Craigslist for the past three days and half of them are scam and half are so expensive it's not worth it," said Peddie.
Carly Fisher came here all the way from Australia.
"It's three days. Back in Australia we only have one-day festivals so to have three days is even better," said Carly Fisher.
Lollapalooza will draw the largest crowd in its history with 270,000 people expected. The Chicago Park District says the festival pumps in $85 million to the local economy with 40 percent of the visitors coming from outside the state.
With about 90,000 people expected each day, the city says police and emergency crews will be on hand. Security cameras are placed around the festival. Cooling buses and water stations will also be available.
Those who weren't lucky enough to get tickets can watch several acts on the Internet. For the first time, Lollapalooza will be streaming live on YouTube at www.youtube.com/lollapalooza.
Lollapalooza runs through Sunday.