"Girl Talk" performs at the Lollapalooza music festival in Grant Park in Chicago
"Girl Talk" performs at the Lollapalooza music festival in Grant Park in Chicago August 5, 2011. The giant rock festival celebrating its 20th anniversary will run three days of music with 140 artists set to perform. Reuters

Mouse ears in the mud. It seemed a fitting end to the 20th anniversary of Lollapalooza, the three-day music festival that started under warm, sunny skies but ended on Sunday night in a rainy dance party.

The Canadian progressive dance music artist deadmau5 -- pronounced like "dead mouse" -- was one of two headliners, along with the Foo Fighters, to close out of the event.

Tens of thousands of fans grooved in puddles to deadmau5's pulsating rhythms, many of them wearing their signature mouse ears on their heads, a seemingly fitting tribute to this year's festival that was heavy on dance music.

A record 270,000 people were estimated to have attended the sold-out Lollapalooza, founded in 1991 by Perry Farrell, frontman of the alternative rock group Jane's Addiction.

British rockers Coldplay and Muse were featured on the festival's first day on Friday while the second day was marked by U.S. hip-hop acts Eminem and Atmosphere and neo-soul artists Cee Lo Green and Mayer Hawthorne, as well as the Country.

Two bands that rose to stardom in the early 1980s each played rousing sets over the weekend, with new wave group The Cars steely performing hits "Good Times Roll" and "Just What I Needed."

Big Audio Dynamite, led by former Clash singer Mick Jones which reunited earlier this year, delivered their mix of arena rock, funk and world music in what seemed a perfect soundtrack for a summer night in Chicago's Grant Park.

EIGHT STAGES, 140 MUSIC ACTS

Over the three-day festival, revelers took in some 140 different musicians on eight different stages, with the two main sets located on separate ends -- more than a mile apart -- of the sprawling park.

"It was the perfect venue. It's a really cool setup," said A.J. Sunder, who traveled to Chicago from Minnesota with his girlfriend and who, at 20 years-old, was born the same year as the first Lollapalooza.

The dance music tent, Perry's Stage, was one of the more popular destinations and on the first night of the concert. Los Angeles dubstep artist Skillrex inspired such an outpouring of people that the stage had to be temporarily shutdown.

Saturday, part of the tent's paneled roofing was removed to allow for better air flow after it became so hot and humid that some concertgoers struggled to catch their breath.

Torrential rain led to an early end of Sunday's show for some, with the crowd noticeably thinner after the downpour.

Sunder, who sought shelter under a nearby parking garage, said it was worthwhile even with the storm.

"I got my money's worth," he said, adding that his personal favorite performance was by the New York electronic act Ratatat.