A fan shows her tattoos as others react as they wait for the Brazilian band Sepultura concert during the Rock in Rio music festival in Rio de Janeiro, Brazil, Sunday Sept. 25, 2011. The festival, which runs through Oct. 2, includes performances by Katy Perry, Rihanna, Stevie Wonder, Red Hot Chili Peppers, Metallica, Guns N' Roses and Coldplay. (AP Photo/Felipe Dana)

Brazil kicked off the world's biggest music festival, Rock in Rio, late Friday with an all-star line-up of top international artists including Rihanna, Kate Perry, Shakira, Elton John and Coldplay.

The event is to attract 700,000 people over its week-long run, with around 100,000 a day turning out to see some of the biggest names in pop and rock belting out tunes on Rio de Janeiro's shoreline.

The mega-show - sold out to ticket-holders paying from 50 to 100 dollars - is taking place in the “City of Rock”, a specially-built venue on the site what will be the future Olympic Village when Rio hosts the 2016 Olympic Games.

Elton John, Kate Perry and Rihanna were to get the party started in the first concerts Friday.

Other artists to follow include Lenny Kravitz, Stevie Wonder, the Red Hot Chili Peppers, Jamiroquai, Metallica, Maroon 5, Guns N' Roses, and top Brazilian singers such as Ivete Sangalo.

“Rock in Rio is to Brazil what Woodstock was to the world,” one of the organizers, Roberta Medina, said.

While still by far the biggest event of its kind on the planet, the size of this year's Rock in Rio is half that of its first edition in 1985, when a staggering 1.4 million people attended to see AC/DC, Iron Maiden, Rod Stewart and - to great enthusiasm - Queen.

The second festival, in 1991, filled Rio's famed Maracana

football stadium with a total audience of 700,000 people and 44

bands. The last one held in Rio, in 2001, attracted 1.2 million people.

Following the huge initial success, Portugal and Spain have also held festivals called Rock in Rio since 2004.

Rio's organizers plan to hold more editions closer together in the future, already confirming Rock in Rio festivals for 2013 and 2015.

“Rock in Rio is to Brazil what Woodstock was to the world,” one of the organizers, Roberta Medina, said.

Stars turning up to perform were making the most of Rio's sunny beaches and effervescent nightlife.

Rihanna, 23, and Kate Perry, 27, were spotted out Thursday night in one of the city's upmarket nightclubs. Rihanna has been in Brazil since mid-September, doing two other shows before joining the opening line-up at Rock in Rio.

According to Rio's tourism officials, the week of concerts is expected to generate 450 million dollars for the city and create 10,000 job, directly and indirectly.

The “City of Rock” was inspired by the US city of New Orleans and features 20 bars and restaurants, 50 shops and various little musical and performance events. It also has a rollercoaster and a giant Ferris wheel. - Sapa-AFP