Country superstars, alt-pop divas, Olympic snowboarders and EDM deities also kept crowds cheering on Saturday in Chicago's Grant Park

After dark on Lollapalooza 2013's second day, Mumford & Sons harmonized their hearts out on the Chicago festival's south end while The Postal Service anchored the north side, capping a perfect sunny Saturday in the park highlighted by inspired sets by Kendrick Lamar (complete with crowd-surfing, wheelchair-bound fans), Ellie Goulding, The National, Eric Church, Court Yard Hounds and even fest founder Perry Farrell sitting in with Olympic snowboarder Shaun White's band Bad Things. Here’s a look of the sights and sounds that highlighted day two of Lolla’s takeover of Grant Park.

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• "We're going to show you how to dance," Marcus Mumford, frontman of the mighty Mumford & Sons, exclaimed ahead of "I Will Wait," half-way through a set that had already seen a traffic jam of fans erupt into spontaneous clap-alongs during nearly every song. The crowd responded in kind with the set's biggest cheer and a starry sea of smartphones held aloft. While the band got enthusiastic hoots all along the way -- including a particularly hearty sing-along to key "Little Lion Man" lyric "I really f*cked it up this time / didn't I, my dear?" -- all the warm, furiously strummed acoustic sounds had to compete not only with Steve Angello's beats from across the way over at Perry's stage, but also with the booming, annual fireworks shooting over nearby Soldier Field in the sky behind them. Still, the band got truly quiet for a beautiful, nearly unplugged cover of Bruce Springsteen's "I'm On Fire," which effectively forced the crowd to concentrate to hear every dulcet note. "Ted's alive," Marcus quipped, nodding to bassist Ted Dwane whose brain surgery nixed the band's Bonnaroo set earlier this summer. In fine form, Dwane worked his bass alongside his bandmates as "The Cave" brought the set to an end.

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• While droves of fans jammed to the folky vibes of Mumford & Sons on the south side of Grant Park, a packed crowd on the north end grooved along to the sleek, electro-pop sounds of the recently reunited Postal Service. The celebrated side project of Death Cab for Cutie’s Ben Gibbard and Dntel (a.k.a. Jimmy Tamborello) hit the stage just after sunset for what would be their second-to-last show ever (the band will end its 10th anniversary reunion trek with a show at Chicago’s club Metro on Sunday). Seeing the end around the corner, the group spared nothing and performed selections from their 2003 album “Give Up” with palpable enthusiasm and pitch-perfect harmonies. Dressed in all black, Gibbard led the charge with jangly guitar melodies and effervescent vocals that floated effortlessly above Tamborello’s easy electronic grooves. Rilo Kiley’s Jenny Lewis joined the group onstage and proved to be Gibbard’s ideal counterpart – the pair’s vocal tug-of-war on “Nothing Better” proved to be one of the show’s highlights. Amidst hits like “Clark Gable,” “We Will Become Silhouettes” and a soaring rendition of their best-known tune “Some Great Heights,” Postal Service also treated the crowd to their recently recorded song “Turn Around” and a cover of Beat Happening’s “Our Secret.” It might be the end of the road for what Gibbard described as his “band from nowhere,” but the group brought Lolla fans to an awesome destination during the last leg of their nostalgic ride.

• A Kendrick Lamar festival set is as much about the crowd participation as it is about the beats and rhymes, and the Compton rapper’s afternoon set on Lolla's Bud Light stage was no different. Between his selections – which included “Bitch, Don’t Kill My Vibe,” “Money Trees,” “Swimming Pools (Drank)” and more jams from his excellent “good kid, m.A.A.d city” album -- Kenrdrick asked the audience to cheer, sing, jump and generally prove why Chicago was the “livest city” he’s been to on tour. During “The Recipe,” the crowd lived up to Lamar’s expectations by hoisting a young man in a wheelchair over their heads, an outrageous gesture that turned the rapper’s head mid-verse. “Oh shit, look at that dude in the wheelchair. Y’all some crazy motherfuckers man,” he responded. As a second wheelchair-bound fan was lifted, Lamar paused the show so the two men could be crowd-surfed to the pit at the front of the stage, where they enjoyed the rest of the show.

• Olympic snowboarder and X-games legend Shaun White and his band Bad Things gave Lollapalooza fans a surprise when the group appeared on the Kidzapalooza stage Saturday afternoon for an unannounced set that featured a guest appearance by Lollapalooza founder and Jane’s Addiction frontman Perry Farrell. But later in the day, the surprise was on the band, who got upgraded to a closing set on the Grove stage – opposite Mumford & Sons and Postal Service – due to Death Grips’ last-minute no show at the festival. It was a daunting slot for the rock quintet, who’ve only played a handful of shows supporting their yet-unreleased debut album and didn’t have quite enough material in their repertoire to fill the 60-minute timeslot. Yet, the group took one for the team and did their best to entertain the small but enthusiastic audience at the wooded stage. The guitar-shredding White may have been the most recognizable face on the stage, but the gold medalist took a backseat as the attention focused on wild-child frontman Davis Leduke, who assaulted the audience with his rowdy antics and growling vocals, which translated well on their inspired cover of Iggy & the Stooges punk classic “Search & Destroy.” Farrell didn’t make it to the stage for Bad Things’ evening slot as rumored, but for those in attendance, the band’s performance remained a memorable way to end the day nonetheless.

Ellie Goulding drew an epic crowd for her Lollapalooza debut on the Bud Light stage, turning sweet songs like "Under The Sheets," "Don't Say A Word" and her sweeping cover of Elton John's "Your Song" into hands-in-the-air festival anthems. She also teased upcoming mini-album "Halcyon Days" (due Aug. 27) with current single "Burn," which was also received rapturously and led to Goulding getting misty at one point from all the support. For her finale, Goulding whipped out a hat trick of her biggest hits -- "Anything Can Happen," "I Need Your Love" and of course "Lights," whose original arrangement was swapped out for the popular Bassnectar remix halfway through and officially flipped the "ape shit" switch for the whole crowd. If the turnout and deafening volume was any indication, Goulding won't be playing daytime slots at festivals like this much longer.

• "I'm all sweaty in this tube top and its puddling. Why did I wear all black?," Court Yard Hounds' Emily Robison laughed after a mellow "Guy Like You" as she and sister Martie Maguire (clad in white) stared into the sun during their easy-going 3PM set on the Lake Shore stage. With Maguire's fiddle and Robison's steel guitar, the sisters (also known as two-thirds of the Dixie Chicks) brought smiles to faces with tunes like "Watch Your Step" and "Then Again."

• Just an hour after Court Yard Hounds’ set, North Carolina country star Eric Church -- whose giant equipment truck with his face and name emblazoned on it was parked just beyond the festival's public area -- kept the Nashville vibes going on the Lake Shore stage. Church jammed his way through favorites like "Springsteen," but ended the set like a true rockstar with "Smoke A Little Smoke" which included a hail of epic guitar chords and, fittingly, smoke machines that shrouded him in clouds of fog.

• There's no escaping the massive dance presence Lollapalooza has built over the years, as kids and older EDM-heads spend their day at the Perry's tent to get their fix of deafening dubstep wobbles and wall-rattling four-on-the-floor beats. (It's also where they get their fair share of chemicals, too, as more stretchers and ambulances were seen exiting the area than any other stage by far.) Some of the acts aren't to everyone's taste beyond the core Electric Daisy-and-co. circuit, but Steve Angello united the crowds with a blistering set and one of his biggest appearances post-Swedish House Mafia's farewell tour earlier this year. By the time he closed with his group's pair of vocal hits, "Save The World" and "Don't You Worry Child," the collective volume could have been heard all the way to Wicker Park.

Haim, one of the most constantly buzzing bands of the year, got a promotion from afternoon act to the second tier, thanks to a last-minute cancellation from headliner Azealia Banks and subsequent reshuffling of the Grove stage. Sisters Este (27), Danielle (24) and Alana (21) Haim demonstrated within seconds why they're all anyone can talk about -- all three are talented multi-instrumentalists with powerful complementary vocals and perform as a striking, cohesive visual balanced between polished and brash. Ranging from more straight-ahead folk-rock tunes to rock burners showcasing Danielle's considerable guitar skill, Haim's set included new pop-leaning single “The Wire” from the band's upcoming debut LP. While noting that their parents were in the audience, the girls also reveled in a neon pink bra that someone in the crowd threw at Alana. “It's a B,” Danielle noted. “Itty-bitty-titty committee, I feel you, girl.”

• One of Lollapalooza's can't-miss Saturday acts that a few too many people missed was Reignwolf, a Canadian blues guitar virtuoso and practically one-man band, save a drummer and a couple of instrumentalists who he invited on stage only when his need to emphatically grip the mic stand precluded him from playing continuous guitar. The ferocious set included a smoldering cover of Fleetwood Mac's “The Chain,” which was slowed down and yet somehow more intense than the original.