Some of the world's biggest names in music were all about Saving Our Selves this weekend.

SOS, of course, refers to the campaign being touted Saturday worldwide at the seven-continent, 24-hour Live Earth: The Concerts for a Climate in Crisis extravaganza, a worldwide shout-out to individuals, political leaders, corporations and every other entity capable of helping put a stop to the environmental scourge that is global warming.

In a partnership with Al Gore's Alliance for Climate Protection and other U.S.-based and international organizations, Live 8 executive producer Kevin Wall put together a bill that included the Police, Madonna, the Red Hot Chili Peppers, Metallica, Foo Fighters, Kelly Clarkson, Roger Waters, John Mayer, the Dave Matthews Band, Bon Jovi, Beastie Boys and more than 100 others for 10 shows in East Rutherford, New Jersey; Washington, D.C.; London; Hamburg, Germany; Shanghai, China; Tokyo; Sydney; Johannesburg, South Africa; Rio de Janeiro, Brazil; and Antarctica (which, yes, featured penguins).

Kicking off in Sydney Friday afternoon (U.S. time) with a performance by the Aussie band Blue King Brown and wrapping up Saturday night to the strains of the Police, Kanye West and John Mayer sending out an SOS in a "Message in a Bottle" at New Jersey's Giants Stadium, Live Earth entertained, excited, sought to educate and pleaded with millions of people who, if they couldn’t be at one of the concerts, could watch online or on more than 100 TV networks (NBC Universal held exclusive U.S. broadcasting rights) or listen on satellite radio.

According to Nielsen Media Research, about 19 million people tuned in to NBC and its affiliated cable networks to watch at least six minutes of the various telecasts, while 2.7 million caught NBC's three-hour prime-time special hosted by Carson Daly and Ann Curry Saturday night.

That means quite a few people needed to have watched the event either overseas or on the Internet to come close to the 2 billion-strong audience Gore and Wall were hoping for but...at least people weren't using too much electricity, right?

Bands big and small trotted out their most appropriately titled tunes in keeping with the message-minded theme, from Melissa Etheridge's Oscar-winning "I Need to Wake Up" from the documentary heard round the world (most importantly in Hollywood) An Inconvenient Truth to Dave Matthews' "Don’t Drink the Water" and "One Sweet World" to John Mayer's "Waiting on the World to Change" to Duran Duran's "Planet Earth."

New Jersey (advertised as New York, just like NFL games) boasted the most starry lineup, with London coming in a close second.

A freshly rehabbed Keith Urban performed one of the first 20-minute sets on what turned out to be a sweltering Saturday in the Garden State, telling the 52,000 people assembled to "start asking questions, guys. It's happened."

KT Tunstall (sporting a "Save the Future" tank top), Ludacris, AFI, Fall Out Boy, Akon (who, yes, took his shirt off—global warming and all), Mayer, a particularly fresh-faced Alicia Keys, West and Clarkson were among the most contemporary acts, while it was up to Bon Jovi, Waters, the Police and—the '90s seem so far away, don’t they—the together-again Smashing Pumpkins to dip into a bag of hits that goes back more than five years.

Actually, while Bon Jovi and the others didn't utter a word that wasn't echoed by thousands of sing-alongers, the Pumpkins were more in yowl mode, with frontman Billy Corgan's guitar wailing enough to make any protester proud and screaming lyrics that may have included the words air pollution. The Chicago-based alt-rockers also did a bit of "Star-Spangled Banner."

Nonmusical A-listers who made the scene to help get the message across included longtime Prius drivers Leonardo DiCaprio and Cameron Diaz ("I've been doing this for years," she said playfully backstage), Kevin Bacon, Zach Braff, Randy Jackson, Rachel Weisz, Abigail Breslin, Rosario Dawson and Alec Baldwin.

"The wonderful thing is, this sets the ball in motion, and what we'll find is that the more we make decisions, the more we push ourselves," Diaz said backstage. "The more solutions we find, the more it's important to us, the more choices we're going to have in all aspects of our lives. And soon, the only choice to be made is the right one."

Etheridge introduced her buddy Al Gore after a rousing performance of an extended version of "I Need to Wake Up," during which the platinum-selling cancer survivor exclaimed, "The whole word is awake! Aren't you glad to be alive right now?!"

"Put all of this energy in your heart and help us solve the climate crisis," a short-sleeved Gore implored, urging  the crowd to sign the seven-point Live Earth pledge to help reverse the climate crisis. The agreement largely emphasizes the idea that even seemingly minor lifestyle adjustments (unplugging appliances while not in use, etc.) can make a huge difference.

Before heading to Jersey, Gore and wife Tipper stopped at the National Mall in D.C., which was just added to the Live Earth itinerary on Friday. Country superstar couple Garth Brooks and Trisha Yearwood were the main attraction.

Meanwhile, London's Wembley Stadium was a-rockin' across the pond, just a week after a musical tribute to Princess Diana was staged there.

"We're here to save the world," British DJ Chris Moyles told the 50,000-strong crowd. "Will you help?!" (The throng answered in the affirmative.)

A video montage accompanied by a barrage of percussion from the Red Hot Chili Peppers' Chad Smith, Queen's Roger Taylor and the Foo Fighters' Taylor Hawkins opened the U.K. show in the early afternoon, giving way to Phil Collins and Genesis, who got the audience going with that "Invisible Touch."

London featured a veritable smorgasbord of socially conscious talent: Damien Rice and David Gray teamed for an ecologically minded version of "Qué Será, Será"; the Black Eyed Peas whipped out a new treatise on global warming ("CO2 levels got the whole planet heated up/ The world is dying, and if they say it's all right then people are lying"); the Pussycat Dolls…um…

Madonna, whose kind of mundane "Hey You" was also shown on massive screens at Giants Stadium (New York Times music critic Jon Pareles pointed out that "Express Yourself" would have served a similar purpose...and been more entertaining to boot), gave a literally showstopping performance, closing out the concert with "Ray of Light."

"Let's hope the concerts that are happening around the world are not just about entertainment but about starting a revolution," the recycled-Material Girl said.

Shakira, who didn't exactly do much to cool the planet with her pelvic-charged rendition of "Hips Don't Lie," headlined the Hamburg show at HSH Nordbank Arena, which also featured Snoop Dogg, Yusuf Islam (aka Cat Stevens), MIA, Chris Cornell and Enrique Iglesias.

Joss Stone joined Angelique Kidjo for the Rolling Stones' "Gimme Shelter" (also covered by Urban and Keys in Jersey) in Johannesburg at the Coca-Cola Dome—featuring globalization in full effect—before UB40 and South African singer-actor Zola shut things down for the night.

Wolfmother, Jack Johnson and a reunited Crowded House headlined the politically charged proceedings at Sydney's Aussie Stadium, which featured a message via satellite from Gore, folk rocker Paul Kelly's "From Little Things Big Things Grow" and a song from the Ghostwriters that went, "Bush is here to steal your oil/ Democracy is foiled, toxic weapons in your soil."

"Say no to nuclear energy" was a common phrase echoed on T-shirts worn onstage throughout the day.

Gore, the decided man of the hour (or rather, 24 hours), then went high-tech in Tokyo, appearing in holographic form to address the crowd, which was treated to Xzibit, Linkin Park and Rihanna at Makuhari Messe.

Shanghai's Oriental Pearl Tower boasted one of the mellower lineups of the day, topped by a number of local acts such as the 12 Girls Band and Broadway and opera star Sarah Brightman, Andrew Lloyd Webber's ex-wife and the original Christine from The Phantom of the Opera.

All systems were go at Rio's Copacabana Beach, where about 400,000 people showed up for the only free concert on Live Earth's docket this year (all proceeds from ticket sales are going to Gore's nonprofit foundation). The concert was almost canceled due to officials' concerns over crowd safety, but Lenny Kravitz, Macy Gray, Pharrell Williams and Brazilian celeb Jorge Ben Jor took the stage as scheduled

And major props to Nunatak, a quintet of guitar, drum, bass, violin and sax-playing scientists stationed at the British Antarctic Service Station in Antarctica. Clad in parkas, ski caps and hipster glasses, natch, the group impressively rocked out on the coldest of our planet's continents to make this a truly global affair.

Live Earth tried its best to be green and "carbon neutral"—biodegradable materials at the concession stands, recycling bins everywhere, generators running on biofuels, nonessential lights turned off between performances, a stage made of recycled tires—but an inevitable criticism was that all that traipsing all over the globe in jets and buses (how many acts carpooled, do you think?) just added more gunk to the atmosphere. The fact that SUV and pickup truck purveyor General Motors was one of the event's main sponsors didn't sit too well with some, either.

Leading up to the event, European papers reported on the enormous "carbon footprint" Madonna has left on the planet, citing her fleet of high-performance cars, her private jet and her recent Confessions tour among her many offenses.

"Madonna's agreeing to sing at Live Earth is merely one of the first steps in her commitment toward being environmentally responsible," the singer's rep said in a statement to Britain's Independent newspaper Sunday.

Live 8 organizer Bob Geldof criticized the event for not having an ultimate goal, saying it would only make a difference if the world's political leaders really woke up and took action. Gore, Wall and others have stressed, however, that Live Earth is only the beginning of what they hope will be a major movement.

Overall, as musicians, actors, politicos and other personalities said throughout the day, Live Earth was about reminding people of their common bond as inhabitants of this planet—which, if you believe what you read, hear and can see with your own eyes, is in major trouble—and about the little things they can do to help.

"If you want to peg me as not being entirely eco-friendly, you'll win," John Mayer told reporters after his set. "We're just getting together to say, 'We want to be healthier.' "