And that's not all. Another Transformers 3 movie shoot is scheduled for the weekend.
So, for city residents, downtown is either the place to be or the place to avoid, depending on your point of view. For music fans, it's like the center of the universe, as Lollapalooza continues at the south end of Grant Park.
Approximately 75,000 music fans are expected to crowd into the park each day. You might think it would be a recipe for trouble. But the vibe is mellow at Lollapalooza -- other than the thousands of fans going crazy for Lady Gaga.
Lady Gaga first appeared on the smallest stage at Lollapalooza three years ago. Now she's one of the biggest names in the music industry. She performed at 8 p.m. Friday.
"She liberates people. She let me be free. One year ago, I wouldn't wear this. I would be seen in public in this," said Hickey.
"She is an idol, someone to look up to," said Cookie Caldwell, Lady Gaga fan.
"It's amazing. Great people, great music, great outfits, great friends," said Alex Snell, Lady Gaga fan.
Fans Christine Hale and Alexis Jennings have been plotting to somehow join their idol in front of the crowd.
"Coming in from the side. That's all I'm gonna say. I can't say anymore. We want to attract a lot of attention. Are we doing well enough?" the pair said.
Jeff and Barbara Duncan drove in from Ann Arbor, Michigan with good reason. The group their son founded in college, My Dear Disco, was getting its big break playing Friday at Lollapallooza.
The parents say they wouldn't have missed it for the world.
"We wondered about it, being one of thousands with these young ones, but he really wanted us to come, and boy are we glad we did! The vibe is already picking up. The buzz is wild!" the couple said.
Other headliners include Green Day and Soundgarden.
Lollapalooza is like an all-you-can-eat buffet for music lovers. Over 3 days, 130 acts take over eight stages.
"The Strokes haven't played in the US in four years. They're my favorite band in the world. This'll be the seventh time seeing 'em. I'll go anywhere they go," said Ken Scalir, who traveled from Los Angeles.
"We drove 9 hours," said Gregory Dobrick, Lollapalooza lover. "There's so many bands and it's not that expensive."
The festival is bigger than ever with more space, which means more walking. It covers nearly a mile stretch of Grant Park.
"So what I would say is just enjoy the process of walking and bumping into new and exciting music that you're going to want for your iPod," said Perry Ferrell, Lollapalooza creator.
In the meantime, the festival apparently is a place to relax for some moms who sent their kids and husbands into the crowd.
"All the kids are down there. We came up here for peace and quie and comfort. It's been a great day," said music fan Joan Cielak.
Bringing 250,000 people into Grant Park over one weekend can cause damage, and that's why local conservationists fought to get concert promoters to agree to return $2 million each year for parkland improvements throughout the city, including the planting of 1,600 trees and shrubs in Grant Park.
"We make sure Grant Park, after every Lollapalooza, looks better than it did when they came in," said Bob O'Neill of the Grant Park Conservancy. "The majority of that money goes out to the neighborhoods for park improvements, playgrounds, trees, gardens all over the city."
Adding to the downtown congestion -- just down the street --another huge crowd gathered inside Soldier Field for Bears Family Night.
"You kind of have to be a big fan to want to watch practice in August," said ABC7's John Garcia.
"Well, I don't like the cold," Bears fan Porsche King responded.
And if that's not enough, Transformers movie shooting continues over the weekend with the city closing down LaSalle between Kinzie and Wacker.
And on the North Side, the Cubs will compete for attention with the tens of thousands who will attend Halsted Street Market Days, with 40 music acts on four stages.
Chicago police will be busy.
"There are a lot of people downtown this weekend, but we're gonna have a lot of police officers there, too," said Supt. Jody Weis.
Lollapalooza uses a large number of extra police officers, but the festival pays all the costs for those officers. It's not part of the city's responsibility; it's like a private security force.
But Weis says, traditionally, there are relatively few problems at Lollapalooza.
Behind-the-scenes at Lollapalooza
- expected crowds: 75,00 per day
- Fri. night's headliner: Lady Gaga
- Saturday: Green Day
- Sunday: Soundgarden
- bigger and better this year: the grounds were expanded to 36 acres
- Columbus now blocked off to traffic
- regular 3-day tickets: $215
- 1-day tickets: $90
- Next year 2011 marks Lollapalooza's 20th anniversary, which promoters promises to be a huge event.