Been a long time for Led Zeppelin

With a thunder of power chords and rock-and-roll swagger, Led Zeppelin broke a silence of two decades Monday in a laser-and-smoke reunion for which more than a million fans from around the world sought to book passage.

The band that boldly breached the barriers between rock, blues and airy mysticism and nurtured a generation on the cusp between the 1960s and 1970s emerged for a sell-out performance in front of about 20,000 concertgoers in east London -- one of the most eagerly awaited rock events of the decade.

“Out there are people from 50 countries, and there’s a sign out there that says ‘Hammer of the Gods,’ ” lead singer Robert Plant said, referring to one of the group’s most famous lyrics, which has also come to be its most enduring motto. “I can’t believe that people from 50 countries would come to see that -- so late in life!” he said wryly.

“This is the 51st country!” he roared then, as the band broke into “Kashmir,” the exotic, melodic and deep-throated anthem that is one of its signatures, against a backdrop of wheeling batik suns and with a sweating, white-haired Jimmy Page on lead guitar.

Concertgoers from as far away as New Zealand, Japan and California made the trek after winning a ticket lottery that allocated a maximum of two seats per person at a price of $250 each, with painstaking care to prevent entries being sold off to scalpers that left some fans waiting three hours in the rain Sunday to secure their seats.

The event was organized as a tribute to the late Ahmet Ertegun, co-founder of Atlantic Records, and also featured performances by Bill Wyman’s Rhythm Kings, led by the former Rolling Stones bassist; Foreigner; Paul Rodgers; and Paolo Nutini.

Led Zeppelin drummer John Bonham’s alcohol-related death in 1980 spelled the end of the band, and Monday’s performance featured Bonham’s son, Jason, now a drummer with Foreigner.

In a city accustomed to cultural happenings, the Led Zeppelin reunion assumed massive proportions, with many here billing it the “concert of the millennium” by “the greatest rock and roll band ever.”

A band that was already being dismissed by critics as self-indulgent by the late 1970s and passe by the time new wave and punk strode onto the stage in the 1980s has suddenly acquired new currency, simultaneously earning the covers this week of Rolling Stone in the U.S. and Q Magazine in the U.K.

“I don’t think they were ever appreciated for the scale of band they were,” Paul Rees, editor of Q, said in an interview. “Maybe it’s a sort of ‘absence makes the heart grow fonder,’ but it’s taken people time to realize the massive influence they had on an awful lot of music.”

“They could be really heavy, but they could also be pastoral. They were ambitious, catchy, they had the whole thing,” said Scott Rowley, editor of Classic Rock magazine. “Is it a nostalgia fest? Yeah, it probably is.”

For many who flooded into London’s O2 Arena, it was an unapologetic trip to a well-remembered past.

“I saw them in ‘73, ’75 and ’77. I’m what you could call hard core. It’s part of your soul. It’s part of everything you did in the ‘70s,” said Tina Ricardo, co-owner of Rick’s Sports Bar in San Francisco, who left her husband at home when she won the ticket lottery and came with her girlfriend.

“How many chances do you get to live something over? That’s it,” she said. “I’m starting to cry now, just thinking about it.”

Likewise for fans from Tokyo. “I saw Led Zeppelin in 1971 and ’72. That was 35 years ago. What can I say? So exciting,” said Yoshihiro Hoshina, 53, who won tickets after entering the lottery with three different e-mail addresses.

“Led Zeppelin broke five hotel rooms in Japan -- that’s a bit of Japan history,” he said before the concert. “But they’re getting old; can Robert Plant sing in that high voice? Can Jimmy Page still play so smooth?”

Answer: pretty much. The 59-year-old Plant had his shirt open modestly to the breastbone, a hint of the bare-abdomened rooster swagger of yesteryear, but managed the high screeches near the end of “Stairway to Heaven” -- still one of the most-played songs on U.S. radio, and which recently entered the charts again last week with the release of Led Zeppelin’s catalog online.

“Hey Ahmet, we did it!” Plant yelled in triumph as the band concluded the song that sounded a bit mystical and silly in the old days but now has an aching touch of lost youth in its hint of possibilities: “Yes there are two paths you can go by, but in the long run, there’s still time to change the road you’re on.”

Or there was.

The Bic lighters once held high by audience members were replaced by the glow of digital cameras and cellphones, but there were still plenty of raised, clenched fists and waving hair -- plus plenty of beer and an occasional waft of marijuana.

A large number of the couples were father and son.

“I introduced my son to it. He wasn’t into it at first, but he changed,” said Owen Williams, 51, from Berkeshire. “He started playing guitar himself, and the Led Zeppelin kicked in; everything changed. He’s stolen all my records and CDs.”

The band opened with a clip from the newly remastered “The Song Remains the Same” DVD depicting the group’s triumphal U.S. gig in 1973 that surpassed a Beatles attendance record, then kicked into “Good Times, Bad Times,” the opening track from its 1969 debut album.

The concert marked the first live performance of “For Your Life,” from the group’s Presence album.

Instead of the old melodramatic hair-swinging and exaggerated erotic strutting, Plant; Page, 63; and bassist John Paul Jones, 61, played the first sets with easygoing confidence. Their good humor built into triumphant intensity as the night wore on; Page pulled out the cello bow on “Dazed and Confused” and worked like a shaman conjurer, glowing under a twirling pyramid of green lasers.

“It’s quite peculiar to imagine. I don’t know how many songs we’ve recorded together, choosing songs from 10 different albums for a dynamic event like this. There are certain songs that have to be there, and this is one of them,” Plant said as the song began.

The finale of “Whole Lotta Love,” played as the first of two encores, was as raw and mesmerizing as ever, and then the band fell into “Rock and Roll” -- It had been a long time, a long lonely, lonely time, and with nothing but rumors of a tour, no one knew for sure when, or if, it would happen again.

kim.murphy@latimes.com